# Greedy algorithm for Egyptian fractions

(Redirected from Egyptian fractions)
Greedy algorithm for Egyptian fractions
You are encouraged to solve this task according to the task description, using any language you may know.

An   Egyptian fraction   is the sum of distinct unit fractions such as:

${\displaystyle {\tfrac {1}{2}}+{\tfrac {1}{3}}+{\tfrac {1}{16}}\,(={\tfrac {43}{48}})}$

Each fraction in the expression has a numerator equal to   1   (unity)   and a denominator that is a positive integer,   and all the denominators are distinct   (i.e., no repetitions).

Fibonacci's   Greedy algorithm for Egyptian fractions   expands the fraction   ${\displaystyle {\tfrac {x}{y}}}$   to be represented by repeatedly performing the replacement

${\displaystyle {\frac {x}{y}}={\frac {1}{\lceil y/x\rceil }}+{\frac {(-y)\!\!\!\!\mod x}{y\lceil y/x\rceil }}}$

(simplifying the 2nd term in this replacement as necessary, and where   ${\displaystyle \lceil x\rceil }$   is the   ceiling   function).

For this task,   Proper and improper fractions   must be able to be expressed.

Proper  fractions   are of the form   ${\displaystyle {\tfrac {a}{b}}}$   where   ${\displaystyle a}$   and   ${\displaystyle b}$   are positive integers, such that   ${\displaystyle a,     and

improper fractions are of the form   ${\displaystyle {\tfrac {a}{b}}}$   where   ${\displaystyle a}$   and   ${\displaystyle b}$   are positive integers, such that   ab.

(See the REXX programming example to view one method of expressing the whole number part of an improper fraction.)

For improper fractions, the integer part of any improper fraction should be first isolated and shown preceding the Egyptian unit fractions, and be surrounded by square brackets [n].

•   show the Egyptian fractions for: ${\displaystyle {\tfrac {43}{48}}}$ and ${\displaystyle {\tfrac {5}{121}}}$ and ${\displaystyle {\tfrac {2014}{59}}}$
•   for all proper fractions,   ${\displaystyle {\tfrac {a}{b}}}$   where   ${\displaystyle a}$   and   ${\displaystyle b}$   are positive one-or two-digit (decimal) integers, find and show an Egyptian fraction that has:
•   the largest number of terms,
•   the largest denominator.
•   for all one-, two-, and three-digit integers,   find and show (as above).     {extra credit}

Also see

## ALGOL 68

Works with: ALGOL 68G version Any - tested with release 2.8.3.win32

Based on the VB.NET sample.
Uses Algol 68G's LONG LONG INT for large integers.

BEGIN # compute some Egytian fractions #
PR precision 2000 PR # set the number of digits for LONG LONG INT #
PROC gcd = ( LONG LONG INT a, b )LONG LONG INT:
IF b = 0 THEN
IF a < 0 THEN
- a
ELSE
a
FI
ELSE
gcd( b, a MOD b )
FI ; # gcd #
MODE RATIONAL       = STRUCT( LONG LONG INT num, den );
MODE LISTOFRATIONAL = STRUCT( RATIONAL element, REF LISTOFRATIONAL next );
REF LISTOFRATIONAL  nil list of rational = NIL;
OP   TOSTRING = (           INT a )STRING: whole( a, 0 );
OP   TOSTRING = (      LONG INT a )STRING: whole( a, 0 );
OP   TOSTRING = ( LONG LONG INT a )STRING: whole( a, 0 );
OP   TOSTRING = (      RATIONAL a )STRING:
IF den OF a = 1
THEN TOSTRING num OF a
ELSE TOSTRING num OF a + "/" + TOSTRING den OF a
FI ; # TOSTRING #
OP   TOSTRING = ( REF LISTOFRATIONAL lr )STRING:
BEGIN
REF LISTOFRATIONAL p      := lr;
STRING             result := "[";
WHILE p ISNT nil list of rational DO
result +:= TOSTRING element OF p;
IF next OF p IS nil list of rational THEN
p := NIL
ELSE
p := next OF p;
result +:= " + "
FI
OD;
result + "]"
END ; # TOSTRING #
OP   CEIL = ( LONG LONG REAL v )LONG LONG INT:
IF LONG LONG INT result := ENTIER v;
ABS v > ABS result
THEN result + 1
ELSE result
FI ;  # CEIL #
OP   EGYPTIAN = ( RATIONAL rp )REF LISTOFRATIONAL:
IF RATIONAL r := rp;
num OF r = 0 OR num OF r = 1
THEN HEAP LISTOFRATIONAL := ( r, nil list of rational )
ELSE
REF LISTOFRATIONAL result     := nil list of rational;
REF LISTOFRATIONAL end result := nil list of rational;
PROC add = ( RATIONAL r )VOID:
IF end result IS nil list of rational THEN
result     := HEAP LISTOFRATIONAL := ( r, nil list of rational );
end result := result
ELSE
next OF end result := HEAP LISTOFRATIONAL := ( r, nil list of rational );
end result         := next OF end result
FI ; # add #
IF num OF r > den OF r THEN
add( RATIONAL( num OF r OVER den OF r, 1 ) );
r := ( num OF r MOD den OF r, den OF r )
FI;
PROC mod func = ( LONG LONG INT m, n )LONG LONG INT: ( ( m MOD n ) + n ) MOD n;
WHILE num OF r /= 0 DO
LONG LONG INT q = CEIL( den OF r / num OF r );
add( RATIONAL( 1, q ) );
r := RATIONAL( mod func( - ( den OF r ), num OF r ), ( den OF r ) * q )
OD;
result
FI ; # EGYPTIAN #
BEGIN # task test cases #
[]RATIONAL test cases = ( RATIONAL( 43, 48 ), RATIONAL( 5, 121 ), RATIONAL( 2014, 59 ) );
FOR r pos FROM LWB test cases TO UPB test cases DO
print( ( TOSTRING test cases[ r pos ], " -> ", TOSTRING EGYPTIAN test cases[ r pos ], newline ) )
OD;
# find the fractions with the most terms and the largest denominator #
print( ( "For rationals with numerator and denominator in 1..99:", newline ) );
RATIONAL           largest denominator  := ( 0, 1 );
REF LISTOFRATIONAL max denominator list := nil list of rational;
LONG LONG INT      max denominator      := 0;
RATIONAL           most terms           := ( 0, 1 );
REF LISTOFRATIONAL most terms list      := nil list of rational;
INT                max terms            := 0;
FOR num TO 99 DO
FOR den TO 99 DO
RATIONAL           r  = RATIONAL( num, den );
REF LISTOFRATIONAL e := EGYPTIAN r;
REF LISTOFRATIONAL p := e;
INT terms := 0;
WHILE p ISNT nil list of rational DO
terms +:= 1;
IF den OF element OF p > max denominator THEN
largest denominator  := r;
max denominator      := den OF element OF p;
max denominator list := e
FI;
p := next OF p
OD;
IF terms > max terms THEN
most terms      := r;
max terms       := terms;
most terms list := e
FI
OD
OD;
print( ( "    ", TOSTRING most terms, " has the most terms: ", TOSTRING max terms, newline
, "    ", TOSTRING most terms list, newline
)
);
print( ( "    ", TOSTRING largest denominator, " has the largest denominator:", newline
, "    ", TOSTRING max denominator list, newline
)
)
END
END
Output:
43/48 -> [1/2 + 1/3 + 1/16]
5/121 -> [1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225]
2014/59 -> [34 + 1/8 + 1/95 + 1/14947 + 1/670223480]
For rationals with numerator and denominator in 1..99:
97/53 has the most terms: 9
[1 + 1/2 + 1/4 + 1/13 + 1/307 + 1/120871 + 1/20453597227 + 1/697249399186783218655 + 1/1458470173998990524806872692984177836808420]
8/97 has the largest denominator:
[1/13 + 1/181 + 1/38041 + 1/1736503177 + 1/3769304102927363485 + 1/18943537893793408504192074528154430149 + 1/538286441900380211365817285104907086347439746130226973253778132494225813153 + 1/579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665]


## C

Output has limited accuracy as noted by comments. The problem requires bigint support to be completely accurate.

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>

typedef int64_t integer;

struct Pair {
integer md;
int tc;
};

integer mod(integer x, integer y) {
return ((x % y) + y) % y;
}

integer gcd(integer a, integer b) {
if (0 == a) return b;
if (0 == b) return a;
if (a == b) return a;
if (a > b) return gcd(a - b, b);
return gcd(a, b - a);
}

void write0(bool show, char *str) {
if (show) {
printf(str);
}
}

void write1(bool show, char *format, integer a) {
if (show) {
printf(format, a);
}
}

void write2(bool show, char *format, integer a, integer b) {
if (show) {
printf(format, a, b);
}
}

struct Pair egyptian(integer x, integer y, bool show) {
struct Pair ret;
integer acc = 0;
bool first = true;

ret.tc = 0;
ret.md = 0;

write2(show, "Egyptian fraction for %lld/%lld: ", x, y);
while (x > 0) {
integer z = (y + x - 1) / x;
if (z == 1) {
acc++;
} else {
if (acc > 0) {
write1(show, "%lld + ", acc);
first = false;
acc = 0;
ret.tc++;
} else if (first) {
first = false;
} else {
write0(show, " + ");
}
if (z > ret.md) {
ret.md = z;
}
write1(show, "1/%lld", z);
ret.tc++;
}
x = mod(-y, x);
y = y * z;
}
if (acc > 0) {
write1(show, "%lld", acc);
ret.tc++;
}
write0(show, "\n");

return ret;
}

int main() {
struct Pair p;
integer nm = 0, dm = 0, dmn = 0, dmd = 0, den = 0;;
int tm, i, j;

egyptian(43, 48, true);
egyptian(5, 121, true); // final term cannot be represented correctly
egyptian(2014, 59, true);

tm = 0;
for (i = 1; i < 100; i++) {
for (j = 1; j < 100; j++) {
p = egyptian(i, j, false);
if (p.tc > tm) {
tm = p.tc;
nm = i;
dm = j;
}
if (p.md > den) {
den = p.md;
dmn = i;
dmd = j;
}
}
}
printf("Term max is %lld/%lld with %d terms.\n", nm, dm, tm); // term max is correct
printf("Denominator max is %lld/%lld\n", dmn, dmd);           // denominator max is not correct
egyptian(dmn, dmd, true);                                     // enough digits cannot be represented without bigint

return 0;
}

Output:
Egyptian fraction for 43/48: 1/2 + 1/3 + 1/16
Egyptian fraction for 5/121: 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1025410058030422033
Egyptian fraction for 2014/59: 34 + 1/8 + 1/95 + 1/14947 + 1/670223480
Term max is 97/53 with 9 terms.
Denominator max is 69/97
Egyptian fraction for 69/97: 1/2 + 1/5 + 1/89 + 1/9593 + 1/118309099 + 1/32659766662805104 + 1/2591418766870639376

## C#

Translation of: Visual Basic .NET
using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using System.Text;

namespace EgyptianFractions {
class Program {
class Rational : IComparable<Rational>, IComparable<int> {
public BigInteger Num { get; }
public BigInteger Den { get; }

public Rational(BigInteger n, BigInteger d) {
var c = Gcd(n, d);
Num = n / c;
Den = d / c;
if (Den < 0) {
Num = -Num;
Den = -Den;
}
}

public Rational(BigInteger n) {
Num = n;
Den = 1;
}

public override string ToString() {
if (Den == 1) {
return Num.ToString();
} else {
return string.Format("{0}/{1}", Num, Den);
}
}

public Rational Add(Rational rhs) {
return new Rational(Num * rhs.Den + rhs.Num * Den, Den * rhs.Den);
}

public Rational Sub(Rational rhs) {
return new Rational(Num * rhs.Den - rhs.Num * Den, Den * rhs.Den);
}

public int CompareTo(Rational rhs) {
var ad = Num * rhs.Den;
var bc = Den * rhs.Num;
}

public int CompareTo(int rhs) {
var ad = Num * rhs;
var bc = Den * rhs;
}
}

static BigInteger Gcd(BigInteger a, BigInteger b) {
if (b == 0) {
if (a < 0) {
return -a;
} else {
return a;
}
} else {
return Gcd(b, a % b);
}
}

static List<Rational> Egyptian(Rational r) {
List<Rational> result = new List<Rational>();

if (r.CompareTo(1) >= 0) {
if (r.Den == 1) {
return result;
}
result.Add(new Rational(r.Num / r.Den));
r = r.Sub(result[0]);
}

BigInteger modFunc(BigInteger m, BigInteger n) {
return ((m % n) + n) % n;
}

while (r.Num != 1) {
var q = (r.Den + r.Num - 1) / r.Num;
r = new Rational(modFunc(-r.Den, r.Num), r.Den * q);
}

return result;
}

static string FormatList<T>(IEnumerable<T> col) {
StringBuilder sb = new StringBuilder();
var iter = col.GetEnumerator();

sb.Append('[');
if (iter.MoveNext()) {
sb.Append(iter.Current);
}
while (iter.MoveNext()) {
sb.AppendFormat(", {0}", iter.Current);
}
sb.Append(']');

return sb.ToString();
}

static void Main() {
List<Rational> rs = new List<Rational> {
new Rational(43, 48),
new Rational(5, 121),
new Rational(2014, 59)
};
foreach (var r in rs) {
Console.WriteLine("{0} => {1}", r, FormatList(Egyptian(r)));
}

var lenMax = Tuple.Create(0UL, new Rational(0));
var denomMax = Tuple.Create(BigInteger.Zero, new Rational(0));

var query = (from i in Enumerable.Range(1, 100)
from j in Enumerable.Range(1, 100)
select new Rational(i, j))
.Distinct()
.ToList();
foreach (var r in query) {
var e = Egyptian(r);
ulong eLen = (ulong) e.Count;
var eDenom = e.Last().Den;
if (eLen > lenMax.Item1) {
lenMax = Tuple.Create(eLen, r);
}
if (eDenom > denomMax.Item1) {
denomMax = Tuple.Create(eDenom, r);
}
}

Console.WriteLine("Term max is {0} with {1} terms", lenMax.Item2, lenMax.Item1);
var dStr = denomMax.Item1.ToString();
Console.WriteLine("Denominator max is {0} with {1} digits {2}...{3}", denomMax.Item2, dStr.Length, dStr.Substring(0, 5), dStr.Substring(dStr.Length - 5, 5));
}
}
}

Output:
43/48 => [1/2, 1/3, 1/16]
5/121 => [1/25, 1/757, 1/763309, 1/873960180913, 1/1527612795642093418846225]
2014/59 => [34, 1/8, 1/95, 1/14947, 1/670223480]
Term max is 97/53 with 9 terms
Denominator max is 8/97 with 150 digits 57950...89665

## C++

Library: Boost

The C++ standard library does not have a "big integer" type, so this solution uses the Boost library.

#include <boost/multiprecision/cpp_int.hpp>
#include <iostream>
#include <optional>
#include <sstream>
#include <string>
#include <vector>

typedef boost::multiprecision::cpp_int integer;

struct fraction {
fraction(const integer& n, const integer& d)
: numerator(n), denominator(d) {}
integer numerator;
integer denominator;
};

integer mod(const integer& x, const integer& y) { return ((x % y) + y) % y; }

size_t count_digits(const integer& i) {
std::ostringstream os;
os << i;
return os.str().length();
}

std::string to_string(const integer& i) {
const int max_digits = 20;
std::ostringstream os;
os << i;
std::string s = os.str();
if (s.length() > max_digits)
s.replace(max_digits / 2, s.length() - max_digits, "...");
return s;
}

std::ostream& operator<<(std::ostream& out, const fraction& f) {
return out << to_string(f.numerator) << '/' << to_string(f.denominator);
}

void egyptian(const fraction& f, std::vector<fraction>& result) {
result.clear();
integer x = f.numerator, y = f.denominator;
while (x > 0) {
integer z = (y + x - 1) / x;
result.emplace_back(1, z);
x = mod(-y, x);
y = y * z;
}
}

void print_egyptian(const std::vector<fraction>& result) {
if (result.empty())
return;
auto i = result.begin();
std::cout << *i++;
for (; i != result.end(); ++i)
std::cout << " + " << *i;
std::cout << '\n';
}

void print_egyptian(const fraction& f) {
std::cout << "Egyptian fraction for " << f << ": ";
integer x = f.numerator, y = f.denominator;
if (x > y) {
std::cout << "[" << x / y << "] ";
x = x % y;
}
std::vector<fraction> result;
egyptian(fraction(x, y), result);
print_egyptian(result);
std::cout << '\n';
}

void show_max_terms_and_max_denominator(const integer& limit) {
size_t max_terms = 0;
std::optional<fraction> max_terms_fraction, max_denominator_fraction;
std::vector<fraction> max_terms_result;
integer max_denominator = 0;
std::vector<fraction> max_denominator_result;
std::vector<fraction> result;
for (integer b = 2; b < limit; ++b) {
for (integer a = 1; a < b; ++a) {
fraction f(a, b);
egyptian(f, result);
if (result.size() > max_terms) {
max_terms = result.size();
max_terms_result = result;
max_terms_fraction = f;
}
const integer& denominator = result.back().denominator;
if (denominator > max_denominator) {
max_denominator = denominator;
max_denominator_result = result;
max_denominator_fraction = f;
}
}
}
std::cout
<< "Proper fractions with most terms and largest denominator, limit = "
<< limit << ":\n\n";
std::cout << "Most terms (" << max_terms
<< "): " << max_terms_fraction.value() << " = ";
print_egyptian(max_terms_result);
std::cout << "\nLargest denominator ("
<< count_digits(max_denominator_result.back().denominator)
<< " digits): " << max_denominator_fraction.value() << " = ";
print_egyptian(max_denominator_result);
}

int main() {
print_egyptian(fraction(43, 48));
print_egyptian(fraction(5, 121));
print_egyptian(fraction(2014, 59));
show_max_terms_and_max_denominator(100);
show_max_terms_and_max_denominator(1000);
return 0;
}

Output:
Egyptian fraction for 43/48: 1/2 + 1/3 + 1/16

Egyptian fraction for 5/121: 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795...3418846225

Egyptian fraction for 2014/59: [34] 1/8 + 1/95 + 1/14947 + 1/670223480

Proper fractions with most terms and largest denominator, limit = 100:

Most terms (8): 44/53 = 1/2 + 1/4 + 1/13 + 1/307 + 1/120871 + 1/20453597227 + 1/6972493991...6783218655 + 1/1458470173...7836808420

Largest denominator (150 digits): 8/97 = 1/13 + 1/181 + 1/38041 + 1/1736503177 + 1/3769304102927363485 + 1/1894353789...8154430149 + 1/5382864419...4225813153 + 1/5795045870...3909789665
Proper fractions with most terms and largest denominator, limit = 1000:

Most terms (13): 641/796 = 1/2 + 1/4 + 1/19 + 1/379 + 1/159223 + 1/28520799973 + 1/9296411783...1338400861 + 1/1008271507...4174730681 + 1/1219933718...8484537833 + 1/1860297848...1025882029 + 1/4614277444...8874327093 + 1/3193733450...1456418881 + 1/2039986670...2410165441

Largest denominator (2847 digits): 36/457 = 1/13 + 1/541 + 1/321409 + 1/114781617793 + 1/1482167225...0844346913 + 1/2510651068...4290086881 + 1/7353930250...3326272641 + 1/6489634815...7391865217 + 1/5264420004...5476206145 + 1/3695215730...1238141889 + 1/2048192894...4706590593 + 1/8390188268...5525592705


## Common Lisp

(defun egyption-fractions (x y &optional acc)
(let* ((a (/ x y)))
(cond
((> (numerator a) (denominator a))
(multiple-value-bind (q r) (floor x y)
(if (zerop r)
(cons q acc)
(egyption-fractions r y (cons q acc)))))
((= (numerator a) 1) (reverse (cons a acc)))
(t (let ((b (ceiling y x)))
(egyption-fractions (mod (- y) x) (* y b) (cons (/ b) acc)))))))

(defun test (n fn)
(car (sort (loop for i from 1 to n append
(loop for j from 2 to n collect
(cons (/ i j) (funcall fn (egyption-fractions i j)))))
#'>
:key #'cdr)))

Output:

Basic tests:

(egyption-fractions 43 48)
(egyption-fractions 5 121)
(egyption-fractions 2014 59)
(egyption-fractions 8 97)
(1/2 1/3 1/16)
(1/25 1/757 1/763309 1/873960180913 1/1527612795642093418846225)
(34 1/8 1/95 1/14947 1/670223480)
(1/13 1/181 1/38041 1/1736503177 1/3769304102927363485
1/18943537893793408504192074528154430149
1/538286441900380211365817285104907086347439746130226973253778132494225813153
1/579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665)

Other tests:

(test 999 #'length)
(test 999 (lambda (xs) (loop for x in xs maximizing (denominator x))))
(493/457 . 13)
(36/457
. 839018826833450186636781520007011999269820404906753180244759299287837378895397605613261469995626498719289835112392530430840514102146998625666594756995273418015600023494049208108894185781774002683063204252356172520941088783702738286944210460710059319691268110283467445381026653628599765684739105388642310044785844902157076919003735231543781785073393176144167688252446541416466418608465458502997971425428342769433127784560570193376772878336217849260872114137931351960543608384244009505664253173875705234889570853924105640193619301332776989688248555027054395237907581951261868280899150574360164800187964167274323078311078867593844043149124596271281252530924719121766925749760855109100066731841478262812686642693395896229983745226277793055820609058348269152190083695704685769622011655159174272326647342695589818127126303038171968768650476413027459205291075571637957597356820188031655122749743652301268394542123970892422944335857917641636041892192547135178153602038877677614358281581103685526041329841496863410305888255234495015115912388514981113593387572720476744188169200130515719608747338810136728267784013352396910979904545913458536243327311977805126410065576961237640824852114328884086581542091492600312838425666927627674227053793897767395465326589843035773944346372949759909905561209334216847158156644884281300512699910530092870919061876615770708519243818676366245477462042294267674677954783726990349386117468071932874021023714524610740225814235147693954027910741673103980749749728106483987721602738673173009362802337092908847797499475895347112889339502928407808058670297722175686638678788738689803945574002805677250463286479363670076942509109589495377221095405979217163821481666646160815221224686562530536116613645305335922819524037829878961518170177968768364853399057357772141655622381280196908637031556436461404285930426436983658106288733881761514992109680298995922754466040011586713812553117621857109517258943846004179432521131844156242428351270188803919554398620084668514054504414062276012292497375238210886595006249453460414790147611422121782194848803348777061816460876697945418158442269512987729152441940326466631610424906158237288218706447963113019239557885486647314085357651895226117364760315394354624547919209138539180807829672545924239541758108877100331729470119526373928796447673951888289511964811633025369821156695934557103429921063387965046715070102916811976552584464153981214277622597308113449320462341683055200576571910241686615924531368198770946893858410058348221985603151428153382461711196734214085852523778422630907646235900752317571022131569421231196329080023952364788544301495422061066036911772385739659997665503832444529713544286955548310166168837889046149061296461059432238621602179724809510024772127497080258401694929973105184832214622785679651550368465524821062859837409907538269572622296774545103747438431266995525592705)


## D

Assuming the Python entry is correct, this code is equivalent. This requires the D module of the Arithmetic/Rational task.

Translation of: Python
import std.stdio, std.bigint, std.algorithm, std.range, std.conv, std.typecons,
arithmetic_rational: Rat = Rational;

Rat[] egyptian(Rat r) pure nothrow {
typeof(return) result;

if (r >= 1) {
if (r.denominator == 1)
return [r, Rat(0, 1)];
result = [Rat(r.numerator / r.denominator, 1)];
r -= result[0];
}

static enum mod = (in BigInt m, in BigInt n) pure nothrow =>
((m % n) + n) % n;

while (r.numerator != 1) {
immutable q = (r.denominator + r.numerator - 1) / r.numerator;
result ~= Rat(1, q);
r = Rat(mod(-r.denominator, r.numerator), r.denominator * q);
}

result ~= r;
return result;
}

void main() {
foreach (immutable r; [Rat(43, 48), Rat(5, 121), Rat(2014, 59)])
writefln("%s => %(%s %)", r, r.egyptian);

Tuple!(size_t, Rat) lenMax;
Tuple!(BigInt, Rat) denomMax;

foreach (immutable r; iota(1, 100).cartesianProduct(iota(1, 100))
.map!(nd => nd[].Rat).array.sort().uniq) {
immutable e = r.egyptian;
immutable eLen = e.length;
immutable eDenom = e.back.denominator;
if (eLen > lenMax[0])
lenMax = tuple(eLen, r);
if (eDenom > denomMax[0])
denomMax = tuple(eDenom, r);
}
writefln("Term max is %s with %d terms", lenMax[1], lenMax[0]);
immutable dStr = denomMax[0].text;
writefln("Denominator max is %s with %d digits %s...%s",
denomMax[1], dStr.length, dStr[0 .. 5], dStr[$- 5 ..$]);
}

Output:
43/48 => 1/2 1/3 1/16
5/121 => 1/25 1/757 1/763309 1/873960180913 1/1527612795642093418846225
2014/59 => 34 1/8 1/95 1/14947 1/670223480
Term max is 97/53 with 9 terms
Denominator max is 8/97 with 150 digits 57950...89665

## Erlang

-module(egypt).

-import(lists, [reverse/1, seq/2]).
-export([frac/2, show/2, rosetta/0]).

rosetta() ->
Fractions = [{N, D, second(frac(N, D))} || N <- seq(2,99), D <- seq(N+1, 99)],
{Longest, A1, B1} = findmax(fun length/1, Fractions),
io:format("~b/~b has ~b terms.~n", [A1, B1, Longest]),
{Largest, A2, B2} = findmax(fun (L) -> hd(reverse(L)) end, Fractions),
io:format("~b/~b has a really long denominator. (~b)~n", [A2, B2, Largest]).

second({_, B}) -> B.

findmax(Fn, L) -> findmax(Fn, L, 0, 0, 0).
findmax(_, [], M, A, B) -> {M, A, B};
findmax(Fn, [{A,B,Frac}|Fracs], M, A0, B0) ->
Val = Fn(Frac),
case Val > M of
true  -> findmax(Fn, Fracs, Val, A, B);
false -> findmax(Fn, Fracs, M, A0, B0)
end.

show(A, B) ->
{W, R} = frac(A, B),
case W of
0 -> ok;
_ -> io:format("[~b] ", [W])
end,
case R of
[] -> ok;
[D0|Ds] ->
io:format("1/~b ", [D0]),
[io:format("+ 1/~b ", [D]) || D <- Ds],
ok
end.

frac(A, B) ->
{A div B, reverse(proper(A rem B, B, []))}.

proper(0, _, L) -> L;
proper(1, Y, L) -> [Y|L];
proper(X, Y, L) ->
D = ceildiv(Y, X),
X2 = mod(-Y, X),
Y2 = Y*ceildiv(Y, X),
proper(X2, Y2, [D|L]).

ceildiv(A, B) ->
Q = A div B,
case A rem B of
0 -> Q;
_ -> Q+1
end.

mod(A, M) ->
B = A rem M,
if
B < 0 -> B + M;
true -> B
end.

Output:
129> egypt:show(43,48).
1/2 + 1/3 + 1/16 ok
130> egypt:show(5,121).
1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225 ok
131> egypt:show(2014,59).
[34] 1/8 + 1/95 + 1/14947 + 1/670223480 ok
132> egypt:rosetta().
8/97 has 8 terms.
8/97 has a really long denominator. (579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665)
ok


## F#

// Greedy algorithm for Egyptian fractions. Nigel Galloway: February 1st., 2023
open Mathnet.Numerics
let fN(g:BigRational)=match bigint.DivRem(g.Denominator,g.Numerator) with (n,g) when g=0I->n |(n,_)->n+1I
let fG(n:BigRational)=Seq.unfold(fun(g:BigRational)->if g.Numerator=0I then None else let i=fN g in Some(i,(g-1N/(BigRational.FromBigInt i))))(n)
let fL(n:bigint,g:seq<bigint>)=printf "%A" n; g|>Seq.iter(printf "+1/%A"); printfn ""
let f2ef(i:BigRational)=let n,g=bigint.DivRem(i.Numerator,i.Denominator) in (n,fG(BigRational.FromBigIntFraction(g,i.Denominator)))
[43N/48N;5N/121N;2014N/59N]|>List.iter(f2ef>>fL)
let n,_=List.allPairs [1N..99N] [1N..99N]|>Seq.map(fun(n,g)->let n=n/g in (n,f2ef n))|>Seq.maxBy(fun(_,(n,g))->Seq.length g + if n>0I then 1 else 0) in printf "%A->" n; (f2ef>>fL)n
let n,_=List.allPairs [1N..999N] [1N..999N]|>Seq.map(fun(n,g)->let n=n/g in (n,f2ef n))|>Seq.maxBy(fun(_,(n,g))->Seq.length g + if n>0I then 1 else 0) in printf "%A->" n; (f2ef>>fL)n
let n,_=List.allPairs [1N..99N] [1N..99N]|>Seq.map(fun(n,g)->let n=n/g in (n,f2ef n))|>Seq.maxBy(fun(_,(n,g))->if Seq.isEmpty g then 0I else Seq.max g) in printf "%A->" n; (f2ef>>fL)n
let n,_=List.allPairs [1N..999N] [1N..999N]|>Seq.map(fun(n,g)->let n=n/g in (n,f2ef n))|>Seq.maxBy(fun(_,(n,g))->if Seq.isEmpty g then 0I else Seq.max g) in printf "%A->" n; (f2ef>>fL)n

Output:
0+1/2+1/3+1/16
0+1/25+1/757+1/763309+1/873960180913+1/1527612795642093418846225
34+1/8+1/95+1/14947+1/670223480
97/53N->1+1/2+1/4+1/13+1/307+1/120871+1/20453597227+1/697249399186783218655+1/1458470173998990524806872692984177836808420
493/457N->1+1/13+1/541+1/321409+1/114781617793+1/14821672255960844346913+1/251065106814993628596500876449600804290086881+1/73539302503361520198362339236500915390885795679264404865887253300925727812630083326272641+1/6489634815217096741758907148982381236931234341288936993640630568353888026513046373352130623124225014404918014072680355409470797372507720812828610332359154836067922616607391865217+1/52644200043597301715163084170074049765863371513744701000308778672552161021188727897845435784419167578097570308323221316037189809321236639774156001218848770417914304730719451756764847141999454715415348579218576135692260706546084789833559164567239198064491721524233401718052341737694961761810858726456915514545036448002629051435498625211733293978125476206145+1/3695215730973720191743335450900515442837964059737103132125137784392340041085824276783333540815086968586494259680343732030671448522298751008735945486795776365973142745077411841504712940444458881229478108614230774637316342940593842925604630011475333378620376362943942755446627099104200059416153812858633723638212819657597061963458758259287734950993940819872945202809437805131650984566124057319228963533088559443909352453788455968978250113376533423265233637558939144535732287317303130488802163512444658441011602922480039143050047663394967808639154754442570791381496210122415541628843804495020590646687354364355396925939868087995781911240513904752765014910531863571167632659092232428610030201325032663259931238141889+1/20481928947653467858867964360215698922460866349989714221296388791180533521147068328398292448571350580917144516243144419767021450972552458770890215041236338405232471846144964422722088363577942656244304369314740680337368003341749927848292268159627280776486153786277410225081205358330757686606252814923029488556248114378465151886875778980493919811102286892641254175976181063891774788890129279669791215911728886439002027991447164421080590166911130116483359749418047307595497010369457711350953018694479942850146580996402187310635505278301929397030213544531068769667892360925519410013180703331321321833900350008776368272790481252519169303988218210095146759870287941250090204506960847016059468728275311477613271084474766715488264771177830115028195215223644336345646870679050787515340804351339449474385172464387868299006904638274425855008729765086091731260299397062138670321522563954731398813138738073326593694555049353805161855854036423870334342280080335804850998490793742536882308453307029152812821729798744074167237835462214043679643723245065093600037959124662392297413473130606861784229249604290090458912391096328362137163951398211801143455350336317188806956746282700489013366856863803112203078858200161688528939040348825835610989725020068306497091337571398894447440161081470240965873628208205669354804691958270783090585006358905094926094885655359774269830169287513005586562246433405044654325439410730648108371520856384706590593+1/839018826833450186636781520007011999269820404906753180244759299287837378895397605613261469995626498719289835112392530430840514102146998625666594756995273418015600023494049208108894185781774002683063204252356172520941088783702738286944210460710059319691268110283467445381026653628599765684739105388642310044785844902157076919003735231543781785073393176144167688252446541416466418608465458502997971425428342769433127784560570193376772878336217849260872114137931351960543608384244009505664253173875705234889570853924105640193619301332776989688248555027054395237907581951261868280899150574360164800187964167274323078311078867593844043149124596271281252530924719121766925749760855109100066731841478262812686642693395896229983745226277793055820609058348269152190083695704685769622011655159174272326647342695589818127126303038171968768650476413027459205291075571637957597356820188031655122749743652301268394542123970892422944335857917641636041892192547135178153602038877677614358281581103685526041329841496863410305888255234495015115912388514981113593387572720476744188169200130515719608747338810136728267784013352396910979904545913458536243327311977805126410065576961237640824852114328884086581542091492600312838425666927627674227053793897767395465326589843035773944346372949759909905561209334216847158156644884281300512699910530092870919061876615770708519243818676366245477462042294267674677954783726990349386117468071932874021023714524610740225814235147693954027910741673103980749749728106483987721602738673173009362802337092908847797499475895347112889339502928407808058670297722175686638678788738689803945574002805677250463286479363670076942509109589495377221095405979217163821481666646160815221224686562530536116613645305335922819524037829878961518170177968768364853399057357772141655622381280196908637031556436461404285930426436983658106288733881761514992109680298995922754466040011586713812553117621857109517258943846004179432521131844156242428351270188803919554398620084668514054504414062276012292497375238210886595006249453460414790147611422121782194848803348777061816460876697945418158442269512987729152441940326466631610424906158237288218706447963113019239557885486647314085357651895226117364760315394354624547919209138539180807829672545924239541758108877100331729470119526373928796447673951888289511964811633025369821156695934557103429921063387965046715070102916811976552584464153981214277622597308113449320462341683055200576571910241686615924531368198770946893858410058348221985603151428153382461711196734214085852523778422630907646235900752317571022131569421231196329080023952364788544301495422061066036911772385739659997665503832444529713544286955548310166168837889046149061296461059432238621602179724809510024772127497080258401694929973105184832214622785679651550368465524821062859837409907538269572622296774545103747438431266995525592705
8/97N->0+1/13+1/181+1/38041+1/1736503177+1/3769304102927363485+1/18943537893793408504192074528154430149+1/538286441900380211365817285104907086347439746130226973253778132494225813153+1/579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665
36/457N->0+1/13+1/541+1/321409+1/114781617793+1/14821672255960844346913+1/251065106814993628596500876449600804290086881+1/73539302503361520198362339236500915390885795679264404865887253300925727812630083326272641+1/6489634815217096741758907148982381236931234341288936993640630568353888026513046373352130623124225014404918014072680355409470797372507720812828610332359154836067922616607391865217+1/52644200043597301715163084170074049765863371513744701000308778672552161021188727897845435784419167578097570308323221316037189809321236639774156001218848770417914304730719451756764847141999454715415348579218576135692260706546084789833559164567239198064491721524233401718052341737694961761810858726456915514545036448002629051435498625211733293978125476206145+1/3695215730973720191743335450900515442837964059737103132125137784392340041085824276783333540815086968586494259680343732030671448522298751008735945486795776365973142745077411841504712940444458881229478108614230774637316342940593842925604630011475333378620376362943942755446627099104200059416153812858633723638212819657597061963458758259287734950993940819872945202809437805131650984566124057319228963533088559443909352453788455968978250113376533423265233637558939144535732287317303130488802163512444658441011602922480039143050047663394967808639154754442570791381496210122415541628843804495020590646687354364355396925939868087995781911240513904752765014910531863571167632659092232428610030201325032663259931238141889+1/20481928947653467858867964360215698922460866349989714221296388791180533521147068328398292448571350580917144516243144419767021450972552458770890215041236338405232471846144964422722088363577942656244304369314740680337368003341749927848292268159627280776486153786277410225081205358330757686606252814923029488556248114378465151886875778980493919811102286892641254175976181063891774788890129279669791215911728886439002027991447164421080590166911130116483359749418047307595497010369457711350953018694479942850146580996402187310635505278301929397030213544531068769667892360925519410013180703331321321833900350008776368272790481252519169303988218210095146759870287941250090204506960847016059468728275311477613271084474766715488264771177830115028195215223644336345646870679050787515340804351339449474385172464387868299006904638274425855008729765086091731260299397062138670321522563954731398813138738073326593694555049353805161855854036423870334342280080335804850998490793742536882308453307029152812821729798744074167237835462214043679643723245065093600037959124662392297413473130606861784229249604290090458912391096328362137163951398211801143455350336317188806956746282700489013366856863803112203078858200161688528939040348825835610989725020068306497091337571398894447440161081470240965873628208205669354804691958270783090585006358905094926094885655359774269830169287513005586562246433405044654325439410730648108371520856384706590593+1/839018826833450186636781520007011999269820404906753180244759299287837378895397605613261469995626498719289835112392530430840514102146998625666594756995273418015600023494049208108894185781774002683063204252356172520941088783702738286944210460710059319691268110283467445381026653628599765684739105388642310044785844902157076919003735231543781785073393176144167688252446541416466418608465458502997971425428342769433127784560570193376772878336217849260872114137931351960543608384244009505664253173875705234889570853924105640193619301332776989688248555027054395237907581951261868280899150574360164800187964167274323078311078867593844043149124596271281252530924719121766925749760855109100066731841478262812686642693395896229983745226277793055820609058348269152190083695704685769622011655159174272326647342695589818127126303038171968768650476413027459205291075571637957597356820188031655122749743652301268394542123970892422944335857917641636041892192547135178153602038877677614358281581103685526041329841496863410305888255234495015115912388514981113593387572720476744188169200130515719608747338810136728267784013352396910979904545913458536243327311977805126410065576961237640824852114328884086581542091492600312838425666927627674227053793897767395465326589843035773944346372949759909905561209334216847158156644884281300512699910530092870919061876615770708519243818676366245477462042294267674677954783726990349386117468071932874021023714524610740225814235147693954027910741673103980749749728106483987721602738673173009362802337092908847797499475895347112889339502928407808058670297722175686638678788738689803945574002805677250463286479363670076942509109589495377221095405979217163821481666646160815221224686562530536116613645305335922819524037829878961518170177968768364853399057357772141655622381280196908637031556436461404285930426436983658106288733881761514992109680298995922754466040011586713812553117621857109517258943846004179432521131844156242428351270188803919554398620084668514054504414062276012292497375238210886595006249453460414790147611422121782194848803348777061816460876697945418158442269512987729152441940326466631610424906158237288218706447963113019239557885486647314085357651895226117364760315394354624547919209138539180807829672545924239541758108877100331729470119526373928796447673951888289511964811633025369821156695934557103429921063387965046715070102916811976552584464153981214277622597308113449320462341683055200576571910241686615924531368198770946893858410058348221985603151428153382461711196734214085852523778422630907646235900752317571022131569421231196329080023952364788544301495422061066036911772385739659997665503832444529713544286955548310166168837889046149061296461059432238621602179724809510024772127497080258401694929973105184832214622785679651550368465524821062859837409907538269572622296774545103747438431266995525592705


## Factor

USING: backtrack formatting fry kernel locals make math
math.functions math.ranges sequences ;
IN: rosetta-code.egyptian-fractions

: >improper ( r -- str ) >fraction "%d/%d" sprintf ;

: improper ( x y -- a b ) [ /i ] [ [ rem ] [ nip ] 2bi / ] 2bi ;

:: proper ( x y -- a b )
y x / ceiling :> d1 1 d1 / y neg x rem y d1 * / ;

: expand ( a -- b c )
>fraction 2dup > [ improper ] [ proper ] if ;

: egyptian-fractions ( x -- seq )
[ [ expand [ , ] dip dup 0 = not ] loop drop ] { } make ;

: part1 ( -- )
43/48 5/121 2014/59 [
[ >improper ] [ egyptian-fractions ] bi
"%s => %[%u, %]\n" printf
] tri@ ;

: all-longest ( seq -- seq )
dup longest length '[ length _ = ] filter ;

: (largest-denominator) ( seq -- n )
[ denominator ] map supremum ;

: most-terms ( seq -- )
all-longest [ [ sum ] map ] [ first length ] bi
"most terms: %[%u, %] => %d\n" printf ;

: largest-denominator ( seq -- )
[ (largest-denominator) ] supremum-by
[ sum ] [ (largest-denominator) ] bi
"largest denominator: %u => %d\n" printf ;

: part2 ( -- )
[
99 [1,b] amb-lazy dup [1,b] amb-lazy swap /
egyptian-fractions
] bag-of [ most-terms ] [ largest-denominator ] bi ;

: egyptian-fractions-demo ( -- ) part1 part2 ;

MAIN: egyptian-fractions-demo

Output:
43/48 => { 1/2, 1/3, 1/16 }
5/121 => { 1/25, 1/757, 1/763309, 1/873960180913, 1/1527612795642093418846225 }
2014/59 => { 34, 1/8, 1/95, 1/14947, 1/670223480 }
most terms: { 44/53, 8/97 } => 8
largest denominator: 8/97 => 579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665


## FreeBASIC

Library: GMP
' version 16-01-2017
' compile with: fbc -s console

#Define max 30

#Include Once "gmp.bi"

Dim Shared As Mpz_ptr num(max), den(max)

Function Egyptian_fraction(fraction As String, ByRef whole As Integer, range As Integer = 0) As Integer

If InStr(fraction,"/") = 0 Then
Print "Not a fraction, program will end"
Sleep 5000, 1
End
End If

Dim As Integer i, count

Dim As Mpz_ptr tmp_num, tmp_den, x, y, q
tmp_num = Allocate(Len(__Mpz_struct)) : Mpz_init(tmp_num)
tmp_den = Allocate(Len(__Mpz_struct)) : Mpz_init(tmp_den)
x = Allocate(Len(__Mpz_struct)) : Mpz_init(x)
y = Allocate(Len(__Mpz_struct)) : Mpz_init(y)
q = Allocate(Len(__Mpz_struct)) : Mpz_init(q)

For i = 1 To max ' clear the list
Mpz_set_ui(num(i), 0)
Mpz_set_ui(den(i), 0)
Next

i = InStr(fraction,"/")
Mpz_set_str(x, Left(fraction, i -1), 10)
Mpz_set_str(y, Right(fraction, Len(fraction) - i), 10)

' if it's a improper fraction make it proper fraction
If Mpz_cmp(x , y) > 0  Then
Mpz_fdiv_q(q, x, y)
whole = Mpz_get_ui(q)
Mpz_fdiv_r(x, x, q)
Else
whole = 0
End If

Mpz_gcd(q, x, y) ' check if reduction is possible
If Mpz_cmp_ui(q, 1) > 0 Then
If range <> 0 Then ' return if we do a range test
Return -1
Else
Mpz_fdiv_q(x, x, q)
Mpz_fdiv_q(y, y, q)
End If
End If

Mpz_set(num(count), x)
Mpz_set(den(count), y)
' Fibonacci's Greedy algorithm for Egyptian fractions
Do
If Mpz_cmp_ui(num(count), 1) = 0 Then Exit Do
Mpz_set(x, num(count))
Mpz_set(y, den(count))
Mpz_cdiv_q(q, y, x)
Mpz_set_ui(num(count), 1)
Mpz_set(den(count), q)
Mpz_mul(tmp_den, y, q)
Mpz_neg(y, y)
Mpz_mod(tmp_num, y, x)
count += 1
Mpz_gcd(q, tmp_num, tmp_den) ' check if reduction is possible
If Mpz_cmp_ui(q, 1) > 0 Then
Mpz_fdiv_q(tmp_num, tmp_num, q)
Mpz_fdiv_q(tmp_den, tmp_den, q)
End If
Mpz_set(num(count), tmp_num)
Mpz_set(den(count), tmp_den)
Loop

Mpz_clear(tmp_num) : Mpz_clear(tmp_den)
Mpz_clear(x) : Mpz_clear(y) :Mpz_clear(q)

Return count

End Function

Sub prt_solution(fraction As String, whole As Integer, count As Integer)

Print fraction; " = ";

If whole <> 0 Then
Print "["; Str(whole); "] + ";
End If

For i As Integer = 0 To count
Gmp_printf("%Zd/%Zd ", num(i), den(i))
If i <> count Then Print "+ ";
Next
Print

End Sub

' ------=< MAIN >=------

Dim As Integer n, d, number, improper, max_term,  max_size
Dim As String str_in, max_term_str, max_size_str, m_str
Dim As ZString Ptr gmp_str : gmp_str = Allocate(1000000)

For n = 0 To max
num(n) = Allocate(Len(__Mpz_struct)) : Mpz_init(num(n))
den(n) = Allocate(Len(__Mpz_struct)) : Mpz_init(den(n))
Next

Data "43/48", "5/121", "2014/59"
' 4/121 = 12/363 = 11/363 + 1/363 = 1/33 + 1/363
' 5/121 = 4/121 + 1/121 = 1/33 + 1/121 + 1/363
' 2014/59 = 34 + 8/59
' 8/59 = 1/8 + 5/472 = 1/8 + 4/472 + 1/472 = 1/8 + 1/118 + 1/472

For n = 1 To 3
number = Egyptian_fraction(str_in, improper)
prt_solution(str_in, improper, number)
Print
Next

Dim As Integer a = 1 , b = 99

Do
For d = a To b
For n = 1 To d -1
str_in = Str(n) + "/" + Str(d)
number = Egyptian_fraction(str_in, improper,1)
If number = -1 Then Continue For ' skip
If number > max_term Then
max_term = number
max_term_str = str_in
ElseIf number = max_term Then
max_term_str += ", " & str_in
End If
Mpz_get_str(gmp_str, 10, den(number))
If Len(*gmp_str) > max_size Then
max_size = Len(*gmp_str)
max_size_str = str_in
m_str = *gmp_str
ElseIf max_size = Len(*gmp_str) Then
max_size_str += ", " & str_in
End If
Next
Next
Print
Print "for 1 to"; Len(Str(b)); " digits"
Print "Largest number of terms is"; max_term +1; " for "; max_term_str
Print "Largest size for denominator is"; max_size; " for "; max_size_str

If b = 999 Then Exit Do
a = b +1 : b = b * 10 +9
Loop

For n = 0 To max
Mpz_clear(num(n))
Mpz_clear(den(n))
Next

DeAllocate(gmp_str)

' empty keyboard buffer
While InKey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
End
Output:
43/48 = 1/2 + 1/3 + 1/16

5/121 = 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225

2014/59 = [34] + 1/8 + 1/95 + 1/14947 + 1/670223480

for 1 to 2 digits
Largest number of terms is 8 for 44/53, 8/97
Largest size for denominator is 150 for 8/97

for 1 to 3 digits
Largest number of terms is 13 for 641/796, 529/914
Largest size for denominator is 2847 for 36/457, 529/914

## Frink

frac[p, q] :=
{
a = makeArray[[0]]
if p > q
{
a.push[floor[p / q]]
p = p mod q
}
while p > 1
{
d = ceil[q / p]
a.push[1/d]
[p, q] = [-q mod p, d q]
}
if p == 1
a.push[1/q]
a
}

showApproximations[false]

egypt[p, q] := join[" + ", frac[p, q]]

rosetta[] :=
{
lMax = 0
longest = 0

dMax = 0
biggest = 0

for n = 1 to 99
for d = n+1 to 99
{
egypt = frac[n, d]
if length[egypt] > lMax
{
lMax = length[egypt]
longest = n/d
}
d2 = denominator[last[egypt, 1]@0]
if d2 > dMax
{
dMax = d2
biggest = n/d
}
}

println["The fraction with the largest number of terms is $longest"] println["The fraction with the largest denominator is$biggest"]
}
Output:
rosetta[]
The fraction with the largest number of terms is 8/97
The fraction with the largest denominator is 8/97

egypt[43,48]
1/2 + 1/3 + 1/16

egypt[5,121]
1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225

egypt[2014,59]
34 + 1/8 + 1/95 + 1/14947 + 1/670223480


## Fōrmulæ

Fōrmulæ programs are not textual, visualization/edition of programs is done showing/manipulating structures but not text. Moreover, there can be multiple visual representations of the same program. Even though it is possible to have textual representation —i.e. XML, JSON— they are intended for storage and transfer purposes more than visualization and edition.

Programs in Fōrmulæ are created/edited online in its website.

In this page you can see and run the program(s) related to this task and their results. You can also change either the programs or the parameters they are called with, for experimentation, but remember that these programs were created with the main purpose of showing a clear solution of the task, and they generally lack any kind of validation.

Solution

Test cases part 1

Test cases part 2

## Go

Translation of: Kotlin

... except that Go already has support for arbitrary precision rational numbers in its standard library.

package main

import (
"fmt"
"math/big"
"strings"
)

var zero = new(big.Int)
var one = big.NewInt(1)

func toEgyptianRecursive(br *big.Rat, fracs []*big.Rat) []*big.Rat {
if br.Num().Cmp(zero) == 0 {
return fracs
}
iquo := new(big.Int)
irem := new(big.Int)
iquo.QuoRem(br.Denom(), br.Num(), irem)
if irem.Cmp(zero) > 0 {
}
rquo := new(big.Rat).SetFrac(one, iquo)
fracs = append(fracs, rquo)
num2 := new(big.Int).Neg(br.Denom())
num2.Rem(num2, br.Num())
if num2.Cmp(zero) < 0 {
}
denom2 := new(big.Int)
denom2.Mul(br.Denom(), iquo)
f := new(big.Rat).SetFrac(num2, denom2)
if f.Num().Cmp(one) == 0 {
fracs = append(fracs, f)
return fracs
}
fracs = toEgyptianRecursive(f, fracs)
return fracs
}

func toEgyptian(rat *big.Rat) []*big.Rat {
if rat.Num().Cmp(zero) == 0 {
return []*big.Rat{rat}
}
var fracs []*big.Rat
if rat.Num().CmpAbs(rat.Denom()) >= 0 {
iquo := new(big.Int)
iquo.Quo(rat.Num(), rat.Denom())
rquo := new(big.Rat).SetFrac(iquo, one)
rrem := new(big.Rat)
rrem.Sub(rat, rquo)
fracs = append(fracs, rquo)
fracs = toEgyptianRecursive(rrem, fracs)
} else {
fracs = toEgyptianRecursive(rat, fracs)
}
return fracs
}

func main() {
fracs := []*big.Rat{big.NewRat(43, 48), big.NewRat(5, 121), big.NewRat(2014, 59)}
for _, frac := range fracs {
list := toEgyptian(frac)
if list[0].Denom().Cmp(one) == 0 {
first := fmt.Sprintf("[%v]", list[0].Num())
temp := make([]string, len(list)-1)
for i := 1; i < len(list); i++ {
temp[i-1] = list[i].String()
}
rest := strings.Join(temp, " + ")
fmt.Printf("%v -> %v + %s\n", frac, first, rest)
} else {
temp := make([]string, len(list))
for i := 0; i < len(list); i++ {
temp[i] = list[i].String()
}
all := strings.Join(temp, " + ")
fmt.Printf("%v -> %s\n", frac, all)
}
}

for _, r := range [2]int{98, 998} {
if r == 98 {
fmt.Println("\nFor proper fractions with 1 or 2 digits:")
} else {
fmt.Println("\nFor proper fractions with 1, 2 or 3 digits:")
}
maxSize := 0
var maxSizeFracs []*big.Rat
maxDen := zero
var maxDenFracs []*big.Rat
var sieve = make([][]bool, r+1) // to eliminate duplicates
for i := 0; i <= r; i++ {
sieve[i] = make([]bool, r+2)
}
for i := 1; i <= r; i++ {
for j := i + 1; j <= r+1; j++ {
if sieve[i][j] {
continue
}
f := big.NewRat(int64(i), int64(j))
list := toEgyptian(f)
listSize := len(list)
if listSize > maxSize {
maxSize = listSize
maxSizeFracs = maxSizeFracs[0:0]
maxSizeFracs = append(maxSizeFracs, f)
} else if listSize == maxSize {
maxSizeFracs = append(maxSizeFracs, f)
}
listDen := list[len(list)-1].Denom()
if listDen.Cmp(maxDen) > 0 {
maxDen = listDen
maxDenFracs = maxDenFracs[0:0]
maxDenFracs = append(maxDenFracs, f)
} else if listDen.Cmp(maxDen) == 0 {
maxDenFracs = append(maxDenFracs, f)
}
if i < r/2 {
k := 2
for {
if j*k > r+1 {
break
}
sieve[i*k][j*k] = true
k++
}
}
}
}
fmt.Println("  largest number of items =", maxSize)
fmt.Println("  fraction(s) with this number :", maxSizeFracs)
md := maxDen.String()
fmt.Print("  largest denominator = ", len(md), " digits, ")
fmt.Print(md[0:20], "...", md[len(md)-20:], "\b\n")
fmt.Println("  fraction(s) with this denominator :", maxDenFracs)
}
}

Output:
43/48 -> 1/2 + 1/3 + 1/16
5/121 -> 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225
2014/59 -> [34] + 1/8 + 1/95 + 1/14947 + 1/670223480

For proper fractions with 1 or 2 digits:
largest number of items = 8
fraction(s) with this number : [8/97 44/53]
largest denominator = 150 digits, 57950458706754280171...62011424993909789665
fraction(s) with this denominator : [8/97]

For proper fractions with 1, 2 or 3 digits:
largest number of items = 13
fraction(s) with this number : [529/914 641/796]
largest denominator = 2847 digits, 83901882683345018663...38431266995525592705
fraction(s) with this denominator : [36/457 529/914]


import Data.Ratio (Ratio, (%), denominator, numerator)

egyptianFraction :: Integral a => Ratio a -> [Ratio a]
egyptianFraction n
| n < 0 = map negate (egyptianFraction (-n))
| n == 0 = []
| x == 1 = [n]
| x > y = (x div y % 1) : egyptianFraction (x mod y % y)
| otherwise = (1 % r) : egyptianFraction ((-y) mod x % (y * r))
where
x = numerator n
y = denominator n
r = y div x + 1


Testing:

λ> :m Test.QuickCheck
λ> quickCheck (\n -> n == (sum $egyptianFraction n)) +++ OK, passed 100 tests.  Tasks: import Data.List (intercalate, maximumBy) import Data.Ord (comparing) task1 = mapM_ run [43 % 48, 5 % 121, 2014 % 59] where run x = putStrLn$ show x ++ " = " ++ result x
result x = intercalate " + " $show <$> egyptianFraction x

maximumBy
(comparing snd)
[ (a % b, length $egyptianFraction (a % b)) | a <- [1 .. n] , b <- [1 .. n] , a < b ] task22 n = maximumBy (comparing snd) [ (a % b, maximum$ map denominator $egyptianFraction (a % b)) | a <- [1 .. n] , b <- [1 .. n] , a < b ]  λ> task1 43 % 48 = 1 % 2 + 1 % 3 + 1 % 16 5 % 121 = 1 % 25 + 1 % 757 + 1 % 763309 + 1 % 873960180913 + 1 % 1527612795642093418846225 2014 % 59 = 34 % 1 + 1 % 8 + 1 % 95 + 1 % 14947 + 1 % 670223480 λ> task21 99 (44 % 53, 8) λ> task22 99 (8 % 97, 579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665) λ> task21 999 (641 % 796,13) λ> task22 999 (529 % 914, 839018826833450186636781520007011999269820404906753180244759299287837378895397605613261469995626498719289835112392530430840514102146998625666594756995273418015600023494049208108894185781774002683063204252356172520941088783702738286944210460710059319691268110283467445381026653628599765684739105388642310044785844902157076919003735231543781785073393176144167688252446541416466418608465458502997971425428342769433127784560570193376772878336217849260872114137931351960543608384244009505664253173875705234889570853924105640193619301332776989688248555027054395237907581951261868280899150574360164800187964167274323078311078867593844043149124596271281252530924719121766925749760855109100066731841478262812686642693395896229983745226277793055820609058348269152190083695704685769622011655159174272326647342695589818127126303038171968768650476413027459205291075571637957597356820188031655122749743652301268394542123970892422944335857917641636041892192547135178153602038877677614358281581103685526041329841496863410305888255234495015115912388514981113593387572720476744188169200130515719608747338810136728267784013352396910979904545913458536243327311977805126410065576961237640824852114328884086581542091492600312838425666927627674227053793897767395465326589843035773944346372949759909905561209334216847158156644884281300512699910530092870919061876615770708519243818676366245477462042294267674677954783726990349386117468071932874021023714524610740225814235147693954027910741673103980749749728106483987721602738673173009362802337092908847797499475895347112889339502928407808058670297722175686638678788738689803945574002805677250463286479363670076942509109589495377221095405979217163821481666646160815221224686562530536116613645305335922819524037829878961518170177968768364853399057357772141655622381280196908637031556436461404285930426436983658106288733881761514992109680298995922754466040011586713812553117621857109517258943846004179432521131844156242428351270188803919554398620084668514054504414062276012292497375238210886595006249453460414790147611422121782194848803348777061816460876697945418158442269512987729152441940326466631610424906158237288218706447963113019239557885486647314085357651895226117364760315394354624547919209138539180807829672545924239541758108877100331729470119526373928796447673951888289511964811633025369821156695934557103429921063387965046715070102916811976552584464153981214277622597308113449320462341683055200576571910241686615924531368198770946893858410058348221985603151428153382461711196734214085852523778422630907646235900752317571022131569421231196329080023952364788544301495422061066036911772385739659997665503832444529713544286955548310166168837889046149061296461059432238621602179724809510024772127497080258401694929973105184832214622785679651550368465524821062859837409907538269572622296774545103747438431266995525592705)  ## J Solution:  ef =: [: (}.~ 0={.) [: (, r2ef)/ 0 1 #: x: r2ef =: (<(<0);0) { ((] , -) >:@:<.&.%)^:((~:<.)@:%)@:{:^:a:  Examples (required):  (; ef)&> 43r48 5r121 2014r59 +-------+--------------------------------------------------------------+ |43r48 |1r2 1r3 1r16 | +-------+--------------------------------------------------------------+ |5r121 |1r25 1r757 1r763309 1r873960180913 1r1527612795642093418846225| +-------+--------------------------------------------------------------+ |2014r59|34 1r8 1r95 1r14947 1r670223480 | +-------+--------------------------------------------------------------+  Examples (extended):  NB. ef for all 1- and 2-digit fractions EF2 =: ef :: _1:&.> (</~ * %/~) i. 10^2x NB. longest ef for 1- or 2-digit fraction ($ #: (i. >./)@:,)#&>EF2
8 97
# ef 8r97
8

NB. largest denom among for 1- and 2-digit fractions
($#: (i. <./)@:|@:(<./&>)@:,) EF2 8 97 _80 ]\ ": % <./ ef 8r97 57950458706754280171310319185991860825103029195219542358352935765389941868634236 0361798689053273749372615043661810228371898539583862011424993909789665 NB. ef for all 1-,2-, and 3-digit fractions EF3 =: ef :: _1:&.> (</~ * %/~) i. 10^3x NB. longest ef for 1-, 2-,or 3-digit fraction ($ #: (i. >./)@:,)#&>EF3
529 914
# ef 529r914
13

NB. largest denom among for 1-, 2-, and 3-digit fractions
($#: (i. <./)@:|@:(<./&>)@:,) EF3 36 457 _80 ]\ ": % <./ ef 36r457 83901882683345018663678152000701199926982040490675318024475929928783737889539760 56132614699956264987192898351123925304308405141021469986256665947569952734180156 00023494049208108894185781774002683063204252356172520941088783702738286944210460 71005931969126811028346744538102665362859976568473910538864231004478584490215707 69190037352315437817850733931761441676882524465414164664186084654585029979714254 28342769433127784560570193376772878336217849260872114137931351960543608384244009 50566425317387570523488957085392410564019361930133277698968824855502705439523790 75819512618682808991505743601648001879641672743230783110788675938440431491245962 71281252530924719121766925749760855109100066731841478262812686642693395896229983 74522627779305582060905834826915219008369570468576962201165515917427232664734269 55898181271263030381719687686504764130274592052910755716379575973568201880316551 22749743652301268394542123970892422944335857917641636041892192547135178153602038 87767761435828158110368552604132984149686341030588825523449501511591238851498111 35933875727204767441881692001305157196087473388101367282677840133523969109799045 45913458536243327311977805126410065576961237640824852114328884086581542091492600 31283842566692762767422705379389776739546532658984303577394434637294975990990556 12093342168471581566448842813005126999105300928709190618766157707085192438186763 66245477462042294267674677954783726990349386117468071932874021023714524610740225 81423514769395402791074167310398074974972810648398772160273867317300936280233709 29088477974994758953471128893395029284078080586702977221756866386787887386898039 45574002805677250463286479363670076942509109589495377221095405979217163821481666 64616081522122468656253053611661364530533592281952403782987896151817017796876836 48533990573577721416556223812801969086370315564364614042859304264369836581062887 33881761514992109680298995922754466040011586713812553117621857109517258943846004 17943252113184415624242835127018880391955439862008466851405450441406227601229249 73752382108865950062494534604147901476114221217821948488033487770618164608766979 45418158442269512987729152441940326466631610424906158237288218706447963113019239 55788548664731408535765189522611736476031539435462454791920913853918080782967254 59242395417581088771003317294701195263739287964476739518882895119648116330253698 21156695934557103429921063387965046715070102916811976552584464153981214277622597 30811344932046234168305520057657191024168661592453136819877094689385841005834822 19856031514281533824617111967342140858525237784226309076462359007523175710221315 69421231196329080023952364788544301495422061066036911772385739659997665503832444 52971354428695554831016616883788904614906129646105943223862160217972480951002477 21274970802584016949299731051848322146227856796515503684655248210628598374099075 38269572622296774545103747438431266995525592705  ## Java Translation of: Kotlin Works with: Java version 9 import java.math.BigDecimal; import java.math.BigInteger; import java.math.MathContext; import java.util.ArrayList; import java.util.Collections; import java.util.List; public class EgyptianFractions { private static BigInteger gcd(BigInteger a, BigInteger b) { if (b.equals(BigInteger.ZERO)) { return a; } return gcd(b, a.mod(b)); } private static class Frac implements Comparable<Frac> { private BigInteger num, denom; public Frac(BigInteger n, BigInteger d) { if (d.equals(BigInteger.ZERO)) { throw new IllegalArgumentException("Parameter d may not be zero."); } BigInteger nn = n; BigInteger dd = d; if (nn.equals(BigInteger.ZERO)) { dd = BigInteger.ONE; } else if (dd.compareTo(BigInteger.ZERO) < 0) { nn = nn.negate(); dd = dd.negate(); } BigInteger g = gcd(nn, dd).abs(); if (g.compareTo(BigInteger.ZERO) > 0) { nn = nn.divide(g); dd = dd.divide(g); } num = nn; denom = dd; } public Frac(int n, int d) { this(BigInteger.valueOf(n), BigInteger.valueOf(d)); } public Frac plus(Frac rhs) { return new Frac( num.multiply(rhs.denom).add(denom.multiply(rhs.num)), rhs.denom.multiply(denom) ); } public Frac unaryMinus() { return new Frac(num.negate(), denom); } public Frac minus(Frac rhs) { return plus(rhs.unaryMinus()); } @Override public int compareTo(Frac rhs) { BigDecimal diff = this.toBigDecimal().subtract(rhs.toBigDecimal()); if (diff.compareTo(BigDecimal.ZERO) < 0) { return -1; } if (BigDecimal.ZERO.compareTo(diff) < 0) { return 1; } return 0; } @Override public boolean equals(Object obj) { if (null == obj || !(obj instanceof Frac)) { return false; } Frac rhs = (Frac) obj; return compareTo(rhs) == 0; } @Override public String toString() { if (denom.equals(BigInteger.ONE)) { return num.toString(); } return String.format("%s/%s", num, denom); } public BigDecimal toBigDecimal() { BigDecimal bdn = new BigDecimal(num); BigDecimal bdd = new BigDecimal(denom); return bdn.divide(bdd, MathContext.DECIMAL128); } public List<Frac> toEgyptian() { if (num.equals(BigInteger.ZERO)) { return Collections.singletonList(this); } List<Frac> fracs = new ArrayList<>(); if (num.abs().compareTo(denom.abs()) >= 0) { Frac div = new Frac(num.divide(denom), BigInteger.ONE); Frac rem = this.minus(div); fracs.add(div); toEgyptian(rem.num, rem.denom, fracs); } else { toEgyptian(num, denom, fracs); } return fracs; } public void toEgyptian(BigInteger n, BigInteger d, List<Frac> fracs) { if (n.equals(BigInteger.ZERO)) { return; } BigDecimal n2 = new BigDecimal(n); BigDecimal d2 = new BigDecimal(d); BigDecimal[] divRem = d2.divideAndRemainder(n2, MathContext.UNLIMITED); BigInteger div = divRem[0].toBigInteger(); if (divRem[1].compareTo(BigDecimal.ZERO) > 0) { div = div.add(BigInteger.ONE); } fracs.add(new Frac(BigInteger.ONE, div)); BigInteger n3 = d.negate().mod(n); if (n3.compareTo(BigInteger.ZERO) < 0) { n3 = n3.add(n); } BigInteger d3 = d.multiply(div); Frac f = new Frac(n3, d3); if (f.num.equals(BigInteger.ONE)) { fracs.add(f); return; } toEgyptian(f.num, f.denom, fracs); } } public static void main(String[] args) { List<Frac> fracs = List.of( new Frac(43, 48), new Frac(5, 121), new Frac(2014, 59) ); for (Frac frac : fracs) { List<Frac> list = frac.toEgyptian(); Frac first = list.get(0); if (first.denom.equals(BigInteger.ONE)) { System.out.printf("%s -> [%s] + ", frac, first); } else { System.out.printf("%s -> %s", frac, first); } for (int i = 1; i < list.size(); ++i) { System.out.printf(" + %s", list.get(i)); } System.out.println(); } for (Integer r : List.of(98, 998)) { if (r == 98) { System.out.println("\nFor proper fractions with 1 or 2 digits:"); } else { System.out.println("\nFor proper fractions with 1, 2 or 3 digits:"); } int maxSize = 0; List<Frac> maxSizeFracs = new ArrayList<>(); BigInteger maxDen = BigInteger.ZERO; List<Frac> maxDenFracs = new ArrayList<>(); boolean[][] sieve = new boolean[r + 1][]; for (int i = 0; i < r + 1; ++i) { sieve[i] = new boolean[r + 2]; } for (int i = 1; i < r; ++i) { for (int j = i + 1; j < r + 1; ++j) { if (sieve[i][j]) continue; Frac f = new Frac(i, j); List<Frac> list = f.toEgyptian(); int listSize = list.size(); if (listSize > maxSize) { maxSize = listSize; maxSizeFracs.clear(); maxSizeFracs.add(f); } else if (listSize == maxSize) { maxSizeFracs.add(f); } BigInteger listDen = list.get(list.size() - 1).denom; if (listDen.compareTo(maxDen) > 0) { maxDen = listDen; maxDenFracs.clear(); maxDenFracs.add(f); } else if (listDen.equals(maxDen)) { maxDenFracs.add(f); } if (i < r / 2) { int k = 2; while (true) { if (j * k > r + 1) break; sieve[i * k][j * k] = true; k++; } } } } System.out.printf(" largest number of items = %s\n", maxSize); System.out.printf("fraction(s) with this number : %s\n", maxSizeFracs); String md = maxDen.toString(); System.out.printf(" largest denominator = %s digits, ", md.length()); System.out.printf("%s...%s\n", md.substring(0, 20), md.substring(md.length() - 20, md.length())); System.out.printf("fraction(s) with this denominator : %s\n", maxDenFracs); } } }  Output: 43/48 -> 1/2 + 1/3 + 1/16 5/121 -> 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225 2014/59 -> [34] + + 1/8 + 1/95 + 1/14947 + 1/670223480 For proper fractions with 1 or 2 digits: largest number of items = 8 fraction(s) with this number : [8/97, 44/53] largest denominator = 150 digits, 57950458706754280171...62011424993909789665 fraction(s) with this denominator : [8/97] For proper fractions with 1, 2 or 3 digits: largest number of items = 13 fraction(s) with this number : [529/914, 641/796] largest denominator = 2847 digits, 83901882683345018663...38431266995525592705 fraction(s) with this denominator : [36/457, 529/914] ## Julia Works with: Julia version 0.6 struct EgyptianFraction{T<:Integer} <: Real int::T frac::NTuple{N,Rational{T}} where N end Base.show(io::IO, ef::EgyptianFraction) = println(io, "[", ef.int, "] ", join(ef.frac, " + ")) Base.length(ef::EgyptianFraction) = !iszero(ef.int) + length(ef.frac) function Base.convert(::Type{EgyptianFraction{T}}, fr::Rational) where T fr, int::T = modf(fr) fractions = Vector{Rational{T}}(0) x::T, y::T = numerator(fr), denominator(fr) iszero(x) && return EgyptianFraction{T}(int, (x // y,)) while x != one(x) push!(fractions, one(T) // cld(y, x)) x, y = mod1(-y, x), y * cld(y, x) d = gcd(x, y) x ÷= d y ÷= d end push!(fractions, x // y) return EgyptianFraction{T}(int, tuple(fractions...)) end Base.convert(::Type{EgyptianFraction}, fr::Rational{T}) where T = convert(EgyptianFraction{T}, fr) Base.convert(::Type{EgyptianFraction{T}}, fr::EgyptianFraction) where T = EgyptianFraction{T}(convert(T, fr.int), convert.(Rational{T}, fr.frac)) Base.convert(::Type{Rational{T}}, fr::EgyptianFraction) where T = T(fr.int) + sum(convert.(Rational{T}, fr.frac)) Base.convert(::Type{Rational}, fr::EgyptianFraction{T}) where T = convert(Rational{T}, fr) @show EgyptianFraction(43 // 48) @show EgyptianFraction{BigInt}(5 // 121) @show EgyptianFraction(2014 // 59) function task(fractions::AbstractVector) fracs = convert(Vector{EgyptianFraction{BigInt}}, fractions) local frlenmax::EgyptianFraction{BigInt} local lenmax = 0 local frdenmax::EgyptianFraction{BigInt} local denmax = 0 for f in fracs if length(f) ≥ lenmax lenmax = length(f) frlenmax = f end if denominator(last(f.frac)) ≥ denmax denmax = denominator(last(f.frac)) frdenmax = f end end return frlenmax, lenmax, frdenmax, denmax end fr = collect((x // y) for x in 1:100 for y in 1:100 if x != y) |> unique frlenmax, lenmax, frdenmax, denmax = task(fr) println("Longest fraction, with length$lenmax: \n", Rational(frlenmax), "\n = ", frlenmax)
println("Fraction with greatest denominator\n(that is $denmax):\n", Rational(frdenmax), "\n = ", frdenmax) println("\n# For 1 digit-integers:") fr = collect((x // y) for x in 1:10 for y in 1:10 if x != y) |> unique frlenmax, lenmax, frdenmax, denmax = task(fr) println("Longest fraction, with length$lenmax: \n", Rational(frlenmax), "\n = ", frlenmax)
println("Fraction with greatest denominator\n(that is $denmax):\n", Rational(frdenmax), "\n = ", frdenmax) println("# For 3 digit-integers:") fr = collect((x // y) for x in 1:1000 for y in 1:1000 if x != y) |> unique frlenmax, lenmax, frdenmax, denmax = task(fr) println("Longest fraction, with length$lenmax: \n", Rational(frlenmax), "\n = ", frlenmax)
println("Fraction with greatest denominator\n(that is $denmax):\n", Rational(frdenmax), "\n = ", frdenmax)  Output: EgyptianFraction(43 // 48) = [0] 1//2 + 1//3 + 1//16 EgyptianFraction{BigInt}(5 // 121) = [0] 1//25 + 1//757 + 1//763309 + 1//873960180913 + 1//1527612795642093418846225 EgyptianFraction(2014 // 59) = [34] 1//8 + 1//95 + 1//14947 + 1//670223480 Longest fraction, with length 9: 97//53 = [1] 1//2 + 1//4 + 1//13 + 1//307 + 1//120871 + 1//20453597227 + 1//697249399186783218655 + 1//1458470173998990524806872692984177836808420 Fraction with greatest denominator (that is 5795045870675428...424993909789665): 8//97 = [0] 1//13 + 1//181 + 1//38041 + 1//1736503177 + 1//3769304102927363485 + 1//18943537893793408504192074528154430149 + [...] # For 1 digit-integers: Longest fraction, with length 4: 10//7 = [1] 1//3 + 1//11 + 1//231 Fraction with greatest denominator (that is 231): 10//7 = [1] 1//3 + 1//11 + 1//231 # For 3 digit-integers: Longest fraction, with length 13: 950//457 = [2] 1//13 + 1//541 + 1//321409 + 1//114781617793 + 1//14821672255960844346913 + ... Fraction with greatest denominator (that is 8390188268334501866367815200...[2847 digits]): 950//457 = [2] 1//13 + 1//541 + 1//321409 + 1//114781617793 + 1//14821672255960844346913... ## Kotlin As the JDK lacks a fraction or rational class, I've included a basic one in the program. // version 1.2.10 import java.math.BigInteger import java.math.BigDecimal import java.math.MathContext val bigZero = BigInteger.ZERO val bigOne = BigInteger.ONE val bdZero = BigDecimal.ZERO val context = MathContext.UNLIMITED fun gcd(a: BigInteger, b: BigInteger): BigInteger = if (b == bigZero) a else gcd(b, a % b) class Frac : Comparable<Frac> { val num: BigInteger val denom: BigInteger constructor(n: BigInteger, d: BigInteger) { require(d != bigZero) var nn = n var dd = d if (nn == bigZero) { dd = bigOne } else if (dd < bigZero) { nn = -nn dd = -dd } val g = gcd(nn, dd).abs() if (g > bigOne) { nn /= g dd /= g } num = nn denom = dd } constructor(n: Int, d: Int) : this(n.toBigInteger(), d.toBigInteger()) operator fun plus(other: Frac) = Frac(num * other.denom + denom * other.num, other.denom * denom) operator fun unaryMinus() = Frac(-num, denom) operator fun minus(other: Frac) = this + (-other) override fun compareTo(other: Frac): Int { val diff = this.toBigDecimal() - other.toBigDecimal() return when { diff < bdZero -> -1 diff > bdZero -> +1 else -> 0 } } override fun equals(other: Any?): Boolean { if (other == null || other !is Frac) return false return this.compareTo(other) == 0 } override fun toString() = if (denom == bigOne) "$num" else "$num/$denom"

fun toBigDecimal() = num.toBigDecimal() / denom.toBigDecimal()

fun toEgyptian(): List<Frac> {
if (num == bigZero) return listOf(this)
val fracs = mutableListOf<Frac>()
if (num.abs() >= denom.abs()) {
val div = Frac(num / denom, bigOne)
val rem = this - div
toEgyptian(rem.num, rem.denom, fracs)
}
else {
toEgyptian(num, denom, fracs)
}
return fracs
}

private tailrec fun toEgyptian(
n: BigInteger,
d: BigInteger,
fracs: MutableList<Frac>
) {
if (n == bigZero) return
val n2 = n.toBigDecimal()
val d2 = d.toBigDecimal()
var divRem = d2.divideAndRemainder(n2, context)
var div = divRem[0].toBigInteger()
if (divRem[1] > bdZero) div++
var n3 = (-d) % n
if (n3 < bigZero) n3 += n
val d3 = d * div
val f = Frac(n3, d3)
if (f.num == bigOne) {
return
}
toEgyptian(f.num, f.denom, fracs)
}
}

fun main(args: Array<String>) {
val fracs = listOf(Frac(43, 48), Frac(5, 121), Frac(2014,59))
for (frac in fracs) {
val list = frac.toEgyptian()
if (list[0].denom == bigOne) {
val first = "[${list[0]}]" println("$frac -> $first +${list.drop(1).joinToString(" + ")}")
}
else {
println("$frac ->${list.joinToString(" + ")}")
}
}

for (r in listOf(98, 998)) {
if (r == 98)
println("\nFor proper fractions with 1 or 2 digits:")
else
println("\nFor proper fractions with 1, 2 or 3 digits:")
var maxSize = 0
var maxSizeFracs = mutableListOf<Frac>()
var maxDen = bigZero
var maxDenFracs = mutableListOf<Frac>()
val sieve = List(r + 1) { BooleanArray(r + 2) }  // to eliminate duplicates
for (i in 1..r) {
for (j in (i + 1)..(r + 1)) {
if (sieve[i][j]) continue
val f = Frac(i, j)
val list = f.toEgyptian()
val listSize = list.size
if (listSize > maxSize) {
maxSize = listSize
maxSizeFracs.clear()
}
else if (listSize == maxSize) {
}
val listDen = list[list.lastIndex].denom
if (listDen > maxDen) {
maxDen = listDen
maxDenFracs.clear()
}
else if (listDen == maxDen) {
}
if (i < r / 2) {
var k = 2
while (true) {
if (j * k > r + 1) break
sieve[i * k][j * k] = true
k++
}
}
}
}
println("  largest number of items = $maxSize") println(" fraction(s) with this number :$maxSizeFracs")
val md = maxDen.toString()
print("  largest denominator = ${md.length} digits, ") println("${md.take(20)}...${md.takeLast(20)}") println(" fraction(s) with this denominator :$maxDenFracs")
}
}

Output:
43/48 -> 1/2 + 1/3 + 1/16
5/121 -> 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225
2014/59 -> [34] + 1/8 + 1/95 + 1/14947 + 1/670223480

For proper fractions with 1 or 2 digits:
largest number of items = 8
fraction(s) with this number : [8/97, 44/53]
largest denominator = 150 digits, 57950458706754280171...62011424993909789665
fraction(s) with this denominator : [8/97]

For proper fractions with 1, 2 or 3 digits:
largest number of items = 13
fraction(s) with this number : [529/914, 641/796]
largest denominator = 2847 digits, 83901882683345018663...38431266995525592705
fraction(s) with this denominator : [36/457, 529/914]


## Mathematica/Wolfram Language

frac[n_] /; IntegerQ[1/n] := frac[n] = {n};
frac[n_] :=
frac[n] =
With[{p = Numerator[n], q = Denominator[n]},
Prepend[frac[Mod[-q, p]/(q Ceiling[1/n])], 1/Ceiling[1/n]]];
disp[f_] :=
StringRiffle[
SequenceCases[f,
l : {_, 1 ...} :>
If[Length[l] == 1 && l[[1]] < 1, ToString[l[[1]], InputForm],
"[" <> ToString[Length[l]] <> "]"]], " + "] <> " = " <>
ToString[Numerator[Total[f]]] <> "/" <>
ToString[Denominator[Total[f]]];
Print[disp[frac[43/48]]];
Print[disp[frac[5/121]]];
Print[disp[frac[2014/59]]];
fracs = Flatten[Table[frac[p/q], {q, 99}, {p, q}], 1];
Print[disp[MaximalBy[fracs, Length@*Union][[1]]]];
Print[disp[MaximalBy[fracs, Denominator@*Last][[1]]]];
fracs = Flatten[Table[frac[p/q], {q, 999}, {p, q}], 1];
Print[disp[MaximalBy[fracs, Length@*Union][[1]]]];
Print[disp[MaximalBy[fracs, Denominator@*Last][[1]]]];

Output:
1/2 + 1/3 + 1/16 = 43/48
1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225 = 5/121
[34] + 1/8 + 1/95 + 1/14947 + 1/670223480 = 2014/59
1/2 + 1/4 + 1/13 + 1/307 + 1/120871 + 1/20453597227 + 1/697249399186783218655 + 1/1458470173998990524806872692984177836808420 = 44/53
1/13 + 1/181 + 1/38041 + 1/1736503177 + 1/3769304102927363485 + 1/18943537893793408504192074528154430149 + 1/538286441900380211365817285104907086347439746130226973253778132494225813153 + 1/579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665 = 8/97
1/2 + 1/4 + 1/19 + 1/379 + 1/159223 + 1/28520799973 + 1/929641178371338400861 + 1/1008271507277592391123742528036634174730681 + 1/1219933718865393655364635368068124756713122928811333803786753398211072842948484537833 + 1/1860297848030936654742608399135821395565274404917258533393305147319524009551744684579405649080712180254407780735949179513154143641842892458088536544987153757401025882029 + 1/4614277444518045184646591832326467411359277711335974416082881814986405515888533562332069783067894981850924485553345190160771506460024406127868096951360637582674289834858262576425271895218431296391169922044160278696744025988461165811212428548328350795432691637759392474030879286312785400132190057899968737693594392669884878193448874327093 + 1/31937334502481972335865307630139228000187060941658399518862518849553429993133277230560087986574331290756232125775998863890963263813589266879406694561350952988662850757053371133819179770003609046815203982179108798005308113258134895569927488690118483730232440575942894680942308888321353318333183158977270294582315388855860989819894602178852719674244639951777398683083694723999674418435726557523519535770015019287382321071804865681731226989916286199314883016472947639367666251368202759691810399195092598892275413777035275182318485652713871000041272524440519262054008953943029365257325370839037761555465335452562216651250516983405134378252470216494582635109781712938341456418881 + 1/2039986670246850822853427080268636607703538330430958135006350872460188775376402385474575383380701179275926633909293920375037781006938834602683282504456671345800481611955974906577358109966753513899436209725756764159504134559394933538420714469300931804842468643272796657406808805007786178371184391663721349034183315512035012402176731111044506314978549915206516847224339930494935465558632905912262959736737614637514921726288403470224139024425700070180324623265095949577758695292697562554242228453440276043742370033993859881981612938703208463591285870376619588297958810138295747858827756577616148419423031480258559516303907719233914603343421735341220080271152090557188286289527661792734931298102513902518914250419121432886312102736349552224188669212688846219382874287241971706387850290821170997846726526589069990513808709560793139660289273086403155344460608865436195352720549406793512677065107181955781264579349071905411393100989250722104770801720673437692418988638492506057962758754921169589084980707251205329924087857682559921447010465898318288868258062129919867004394488124710647843586978379399594154917914477913086776811741840849911967039211773201428676384229432761943488196359561416605048969002045397348240530911560634680322446588472763785839765588633770016209055874572792498932175778494089116461654628549726895871636209026849103988563732410165441 = 641/796
1/13 + 1/541 + 1/321409 + 1/114781617793 + 1/14821672255960844346913 + 1/251065106814993628596500876449600804290086881 + 1/73539302503361520198362339236500915390885795679264404865887253300925727812630083326272641 + 1/6489634815217096741758907148982381236931234341288936993640630568353888026513046373352130623124225014404918014072680355409470797372507720812828610332359154836067922616607391865217 + 1/52644200043597301715163084170074049765863371513744701000308778672552161021188727897845435784419167578097570308323221316037189809321236639774156001218848770417914304730719451756764847141999454715415348579218576135692260706546084789833559164567239198064491721524233401718052341737694961761810858726456915514545036448002629051435498625211733293978125476206145 + 1/3695215730973720191743335450900515442837964059737103132125137784392340041085824276783333540815086968586494259680343732030671448522298751008735945486795776365973142745077411841504712940444458881229478108614230774637316342940593842925604630011475333378620376362943942755446627099104200059416153812858633723638212819657597061963458758259287734950993940819872945202809437805131650984566124057319228963533088559443909352453788455968978250113376533423265233637558939144535732287317303130488802163512444658441011602922480039143050047663394967808639154754442570791381496210122415541628843804495020590646687354364355396925939868087995781911240513904752765014910531863571167632659092232428610030201325032663259931238141889 + 1/20481928947653467858867964360215698922460866349989714221296388791180533521147068328398292448571350580917144516243144419767021450972552458770890215041236338405232471846144964422722088363577942656244304369314740680337368003341749927848292268159627280776486153786277410225081205358330757686606252814923029488556248114378465151886875778980493919811102286892641254175976181063891774788890129279669791215911728886439002027991447164421080590166911130116483359749418047307595497010369457711350953018694479942850146580996402187310635505278301929397030213544531068769667892360925519410013180703331321321833900350008776368272790481252519169303988218210095146759870287941250090204506960847016059468728275311477613271084474766715488264771177830115028195215223644336345646870679050787515340804351339449474385172464387868299006904638274425855008729765086091731260299397062138670321522563954731398813138738073326593694555049353805161855854036423870334342280080335804850998490793742536882308453307029152812821729798744074167237835462214043679643723245065093600037959124662392297413473130606861784229249604290090458912391096328362137163951398211801143455350336317188806956746282700489013366856863803112203078858200161688528939040348825835610989725020068306497091337571398894447440161081470240965873628208205669354804691958270783090585006358905094926094885655359774269830169287513005586562246433405044654325439410730648108371520856384706590593 + 1/839018826833450186636781520007011999269820404906753180244759299287837378895397605613261469995626498719289835112392530430840514102146998625666594756995273418015600023494049208108894185781774002683063204252356172520941088783702738286944210460710059319691268110283467445381026653628599765684739105388642310044785844902157076919003735231543781785073393176144167688252446541416466418608465458502997971425428342769433127784560570193376772878336217849260872114137931351960543608384244009505664253173875705234889570853924105640193619301332776989688248555027054395237907581951261868280899150574360164800187964167274323078311078867593844043149124596271281252530924719121766925749760855109100066731841478262812686642693395896229983745226277793055820609058348269152190083695704685769622011655159174272326647342695589818127126303038171968768650476413027459205291075571637957597356820188031655122749743652301268394542123970892422944335857917641636041892192547135178153602038877677614358281581103685526041329841496863410305888255234495015115912388514981113593387572720476744188169200130515719608747338810136728267784013352396910979904545913458536243327311977805126410065576961237640824852114328884086581542091492600312838425666927627674227053793897767395465326589843035773944346372949759909905561209334216847158156644884281300512699910530092870919061876615770708519243818676366245477462042294267674677954783726990349386117468071932874021023714524610740225814235147693954027910741673103980749749728106483987721602738673173009362802337092908847797499475895347112889339502928407808058670297722175686638678788738689803945574002805677250463286479363670076942509109589495377221095405979217163821481666646160815221224686562530536116613645305335922819524037829878961518170177968768364853399057357772141655622381280196908637031556436461404285930426436983658106288733881761514992109680298995922754466040011586713812553117621857109517258943846004179432521131844156242428351270188803919554398620084668514054504414062276012292497375238210886595006249453460414790147611422121782194848803348777061816460876697945418158442269512987729152441940326466631610424906158237288218706447963113019239557885486647314085357651895226117364760315394354624547919209138539180807829672545924239541758108877100331729470119526373928796447673951888289511964811633025369821156695934557103429921063387965046715070102916811976552584464153981214277622597308113449320462341683055200576571910241686615924531368198770946893858410058348221985603151428153382461711196734214085852523778422630907646235900752317571022131569421231196329080023952364788544301495422061066036911772385739659997665503832444529713544286955548310166168837889046149061296461059432238621602179724809510024772127497080258401694929973105184832214622785679651550368465524821062859837409907538269572622296774545103747438431266995525592705 = 36/457

## Microsoft Small Basic

Small Basic but large (not huge) integers.

'Egyptian fractions - 26/07/2018
xx=2014
yy=59
x=xx
y=yy
If x>=y Then
q=Math.Floor(x/y)
tt="+("+q+")"
x=Math.Remainder(x,y)
EndIf
If x<>0 Then
While x<>1
'i=modulo(-y,x)
u=-y
v=x
modulo()
i=ret
k=Math.Ceiling(y/x)
m=m+1
tt=tt+"+1/"+k
j=y*k
If i=1 Then
tt=tt+"+1/"+j
EndIf
'n=gcd(i,j)
x=i
y=j
gcd()
n=ret
x=i/n
y=j/n
EndWhile
EndIf
TextWindow.WriteLine(xx+"/"+yy+"="+Text.GetSubTextToEnd(tt,2))

Sub modulo
wr=Math.Remainder(u,v)
While wr<0
wr=wr+v
EndWhile
ret=wr
EndSub

Sub gcd
wx=i
wy=j
wr=1
While wr<>0
wr=Math.Remainder(wx,wy)
wx=wy
wy=wr
EndWhile
ret=wx
EndSub
Output:
43/48=1/2+1/3
5/121=1/25+1/757+1/763309+1/873960180913+1/1527612795642093418846225
2014/59=(34)+1/8+1/95+1/14947+1/670223480


## Nim

Translation of: Go
Library: bignum
import strformat, strutils
import bignum

let
Zero = newInt(0)
One = newInt(1)

#---------------------------------------------------------------------------------------------------

proc toEgyptianrecursive(rat: Rat; fracs: seq[Rat]): seq[Rat] =

if rat.isZero: return fracs

let iquo = cdiv(rat.denom, rat.num)
let rquo = newRat(1, iquo)
result = fracs & rquo
let num2 = cmod(-rat.denom, rat.num)
if num2 < Zero:
num2 += rat.num
let denom2 = rat.denom * iquo
let f = newRat(num2, denom2)
if f.num == One:
else:
result = f.toEgyptianrecursive(result)

#---------------------------------------------------------------------------------------------------

proc toEgyptian(rat: Rat): seq[Rat] =

if rat.num.isZero: return @[rat]

if abs(rat.num) >= rat.denom:
let iquo = rat.num div rat.denom
let rquo = newRat(iquo, 1)
let rrem = rat - rquo
result = rrem.toEgyptianrecursive(@[rquo])
else:
result = rat.toEgyptianrecursive(@[])

#———————————————————————————————————————————————————————————————————————————————————————————————————

for frac in [newRat(43, 48), newRat(5, 121), newRat(2014, 59)]:
let list = frac.toEgyptian()
if list[0].denom == One:
let first = fmt"[{list[0].num}]"
let rest = list[1..^1].join(" + ")
echo fmt"{frac} -> {first} + {rest}"
else:
let all = list.join(" + ")
echo fmt"{frac} -> {all}"

for r in [98, 998]:
if r == 98:
echo "\nFor proper fractions with 1 or 2 digits:"
else:
echo "\nFor proper fractions with 1, 2 or 3 digits:"

var maxSize = 0
var maxSizeFracs: seq[Rat]
var maxDen = Zero
var maxDenFracs: seq[Rat]
var sieve = newSeq[seq[bool]](r + 1)  # To eliminate duplicates.

for item in sieve.mitems: item.setLen(r + 2)
for i in 1..r:
for j in (i + 1)..(r + 1):
if sieve[i][j]: continue

let f = newRat(i, j)
let list = f.toEgyptian()
let listSize = list.len
if listSize > maxSize:
maxSize = listSize
maxSizeFracs.setLen(0)
elif listSize == maxSize:

let listDen = list[^1].denom()
if listDen > maxDen:
maxDen = listDen
maxDenFracs.setLen(0)
elif listDen == maxDen:

if i < r div 2:
var k = 2
while j * k <= r + 1:
sieve[i * k][j * k] = true
inc k

echo fmt"  largest number of items = {maxSize}"
echo fmt"  fraction(s) with this number : {maxSizeFracs.join("", "")}"
let md = $maxDen echo fmt" largest denominator = {md.len} digits, {md[0..19]}...{md[^20..^1]}" echo fmt" fraction(s) with this denominator : {maxDenFracs.join("", "")}"  Output: 43/48 -> 1/2 + 1/3 + 1/16 5/121 -> 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225 2014/59 -> [34] + 1/8 + 1/95 + 1/14947 + 1/670223480 For proper fractions with 1 or 2 digits: largest number of items = 8 fraction(s) with this number : 8/97, 44/53 largest denominator = 150 digits, 57950458706754280171...62011424993909789665 fraction(s) with this denominator : 8/97 For proper fractions with 1, 2 or 3 digits: largest number of items = 13 fraction(s) with this number : 529/914, 641/796 largest denominator = 2847 digits, 83901882683345018663...38431266995525592705 fraction(s) with this denominator : 36/457, 529/914 ## PARI/GP efrac(f)=my(v=List());while(f,my(x=numerator(f),y=denominator(f));listput(v,ceil(y/x));f=(-y)%x/y/v[#v]);Vec(v); show(f)=my(n=f\1,v=efrac(f-n)); print1(f" = ["n"; "v[1]); for(i=2,#v,print1(", "v[i])); print("]"); best(n)=my(denom,denomAt,term,termAt,v); for(a=1,n-1,for(b=a+1,n, v=efrac(a/b); if(#v>term, termAt=a/b; term=#v); if(v[#v]>denom, denomAt=a/b; denom=v[#v]))); print("Most terms is "termAt" with "term); print("Biggest denominator is "denomAt" with "denom) apply(show, [43/48, 5/121, 2014/59]); best(9) best(99) best(999) Output: 43/48 = [0; 2, 3, 16] 5/121 = [0; 25, 757, 763309, 873960180913, 1527612795642093418846225] 2014/59 = [34; 8, 95, 14947, 670223480] Most terms is 3/7 with 3 Biggest denominator is 3/7 with 231 Most terms is 8/97 with 8 Biggest denominator is 8/97 with 579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665 Most terms is 529/914 with 13 Biggest denominator is 36/457 with 839...705 ## Perl use strict; use warnings; use bigint; sub isEgyption{ my$nr = int($_[0]); my$de = int($_[1]); if($nr == 0 or $de == 0){ #Invalid input return; } if($de % $nr == 0){ # They divide so print printf "1/" . int($de/$nr); return; } if($nr % $de == 0){ # Invalid fraction printf$nr/$de; return; } if($nr > $de){ printf int($nr/$de) . " + "; isEgyption($nr%$de,$de);
return;
}
# Floor to find ceiling and print as fraction
my $tmp = int($de/$nr) + 1; printf "1/" .$tmp . " + ";
isEgyption($nr*$tmp-$de,$de*$tmp); } my$nrI = 2014;
my $deI = 59; printf "\nEgyptian Fraction Representation of " .$nrI . "/" . $deI . " is: \n\n"; isEgyption($nrI,$deI);  Output: Egyptian Fraction Representation of 2014/59 is: 34 + 1/8 + 1/95 + 1/14947 + 1/670223480  ## Phix Translation of: tcl Library: Phix/mpfr The sieve copied from Go with javascript_semantics include mpfr.e function egyptian(integer num, denom) mpz n = mpz_init(num), d = mpz_init(denom), t = mpz_init() sequence result = {} while mpz_cmp_si(n,0)!=0 do mpz_cdiv_q(t, d, n) result = append(result,"1/"&mpz_get_str(t)) mpz_neg(d,d) mpz_mod(n,d,n) mpz_neg(d,d) mpz_mul(d,d,t) end while {n,d} = mpz_free({n,d}) return result end function procedure efrac(integer num, denom) string fraction = sprintf("%d/%d",{num,denom}), prefix = "" if num>=denom then integer whole = floor(num/denom) num -= whole*denom prefix = sprintf("[%d] + ",whole) end if string e = join(egyptian(num, denom)," + ") printf(1,"%s -> %s%s\n",{fraction,prefix,e}) end procedure efrac(43,48) efrac(5,121) efrac(2014,59) integer maxt = 0, maxd = 0 string maxts = "", maxds = "", maxda = "" for r=98 to 998 by 900 do -- (iterates just twice!) sequence sieve = repeat(repeat(false,r+1),r) -- to eliminate duplicates for n=1 to r do for d=n+1 to r+1 do if sieve[n][d]=false then string term = sprintf("%d/%d",{n,d}) sequence terms = egyptian(n,d) integer nterms = length(terms) if nterms>maxt then maxt = nterms maxts = term elsif nterms=maxt then maxts &= ", " & term end if integer mlen = length(terms[$])-2
if mlen>maxd then
maxd = mlen
maxds = term
maxda = terms[$] elsif mlen=maxd then maxds &= ", " & term end if if n<r/2 then for k=2 to 9999 do if d*k > r+1 then exit end if sieve[n*k][d*k] = true end for end if end if end for end for printf(1,"\nfor proper fractions with 1 to %d digits\n",{length(sprint(r))}) printf(1,"Largest number of terms is %d for %s\n",{maxt,maxts}) maxda = maxda[3..$] -- (strip the "1/")
maxda[6..-6]="..."  -- (show only first/last 5 digits)
printf(1,"Largest size for denominator is %d digits (%s) for %s\n",{maxd,maxda,maxds})
end for

Output:
43/48 -> 1/2 + 1/3 + 1/16
5/121 -> 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225
2014/59 -> [34] + 1/8 + 1/95 + 1/14947 + 1/670223480

for proper fractions with 1 to 2 digits
Largest number of terms is 8 for 8/97, 44/53
Largest size for denominator is 150 digits (57950...89665) for 8/97

for proper fractions with 1 to 3 digits
Largest number of terms is 13 for 529/914, 641/796
Largest size for denominator is 2847 digits (83901...92705) for 36/457, 529/914


## Prolog

Works with: SWI Prolog
count_digits(Number, Count):-
atom_number(A, Number),
atom_length(A, Count).

integer_to_atom(Number, Atom):-
atom_number(A, Number),
atom_length(A, Count),
(Count =< 20 ->
Atom = A
;
sub_atom(A, 0, 10, _, A1),
P is Count - 10,
sub_atom(A, P, 10, _, A2),
atom_concat(A1, '...', A3),
atom_concat(A3, A2, Atom)
).

egyptian(0, _, []):- !.
egyptian(X, Y, [Z|E]):-
Z is (Y + X - 1)//X,
X1 is -Y mod X,
Y1 is Y * Z,
egyptian(X1, Y1, E).

print_egyptian([]):- !.
print_egyptian([N|List]):-
integer_to_atom(N, A),
write(1/A),
(List = [] -> true; write(' + ')),
print_egyptian(List).

print_egyptian(X, Y):-
writef('Egyptian fraction for %t/%t: ', [X, Y]),
(X > Y ->
N is X//Y,
writef('[%t] ', [N]),
X1 is X mod Y
;
X1 = X
),
egyptian(X1, Y, E),
print_egyptian(E),
nl.

max_terms_and_denominator1(D, Max_terms, Max_denom, Max_terms1, Max_denom1):-
max_terms_and_denominator1(D, 1, Max_terms, Max_denom, Max_terms1, Max_denom1).

max_terms_and_denominator1(D, D, Max_terms, Max_denom, Max_terms, Max_denom):- !.
max_terms_and_denominator1(D, N, Max_terms, Max_denom, Max_terms1, Max_denom1):-
Max_terms1 = f(_, _, _, Len1),
Max_denom1 = f(_, _, _, Max1),
egyptian(N, D, E),
length(E, Len),
last(E, Max),
(Len > Len1 ->
Max_terms2 = f(N, D, E, Len)
;
Max_terms2 = Max_terms1
),
(Max > Max1 ->
Max_denom2 = f(N, D, E, Max)
;
Max_denom2 = Max_denom1
),
N1 is N + 1,
max_terms_and_denominator1(D, N1, Max_terms, Max_denom, Max_terms2, Max_denom2).

max_terms_and_denominator(N, Max_terms, Max_denom):-
max_terms_and_denominator(N, 1, Max_terms, Max_denom, f(0, 0, [], 0),
f(0, 0, [], 0)).

max_terms_and_denominator(N, N, Max_terms, Max_denom, Max_terms, Max_denom):-!.
max_terms_and_denominator(N, N1, Max_terms, Max_denom, Max_terms1, Max_denom1):-
max_terms_and_denominator1(N1, Max_terms2, Max_denom2, Max_terms1, Max_denom1),
N2 is N1 + 1,
max_terms_and_denominator(N, N2, Max_terms, Max_denom, Max_terms2, Max_denom2).

show_max_terms_and_denominator(N):-
writef('Proper fractions with most terms and largest denominator, limit = %t:\n', [N]),
max_terms_and_denominator(N, f(N_max_terms, D_max_terms, E_max_terms, Len),
f(N_max_denom, D_max_denom, E_max_denom, Max)),
writef('Most terms (%t): %t/%t = ', [Len, N_max_terms, D_max_terms]),
print_egyptian(E_max_terms),
nl,
count_digits(Max, Digits),
writef('Largest denominator (%t digits): %t/%t = ', [Digits, N_max_denom, D_max_denom]),
print_egyptian(E_max_denom),
nl.

main:-
print_egyptian(43, 48),
print_egyptian(5, 121),
print_egyptian(2014, 59),
nl,
show_max_terms_and_denominator(100),
nl,
show_max_terms_and_denominator(1000).

Output:
Egyptian fraction for 43/48: 1/2 + 1/3 + 1/16
Egyptian fraction for 5/121: 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795...3418846225
Egyptian fraction for 2014/59: [34] 1/8 + 1/95 + 1/14947 + 1/670223480

Proper fractions with most terms and largest denominator, limit = 100:
Most terms (8): 44/53 = 1/2 + 1/4 + 1/13 + 1/307 + 1/120871 + 1/20453597227 + 1/6972493991...6783218655 + 1/1458470173...7836808420
Largest denominator (150 digits): 8/97 = 1/13 + 1/181 + 1/38041 + 1/1736503177 + 1/3769304102927363485 + 1/1894353789...8154430149 + 1/5382864419...4225813153 + 1/5795045870...3909789665

Proper fractions with most terms and largest denominator, limit = 1000:
Most terms (13): 641/796 = 1/2 + 1/4 + 1/19 + 1/379 + 1/159223 + 1/28520799973 + 1/9296411783...1338400861 + 1/1008271507...4174730681 + 1/1219933718...8484537833 + 1/1860297848...1025882029 + 1/4614277444...8874327093 + 1/3193733450...1456418881 + 1/2039986670...2410165441
Largest denominator (2847 digits): 36/457 = 1/13 + 1/541 + 1/321409 + 1/114781617793 + 1/1482167225...0844346913 + 1/2510651068...4290086881 + 1/7353930250...3326272641 + 1/6489634815...7391865217 + 1/5264420004...5476206145 + 1/3695215730...1238141889 + 1/2048192894...4706590593 + 1/8390188268...5525592705


## Python

### Procedural

from fractions import Fraction
from math import ceil

class Fr(Fraction):
def __repr__(self):
return '%s/%s' % (self.numerator, self.denominator)

def ef(fr):
ans = []
if fr >= 1:
if fr.denominator == 1:
return [[int(fr)], Fr(0, 1)]
intfr = int(fr)
ans, fr = [[intfr]], fr - intfr
x, y = fr.numerator, fr.denominator
while x != 1:
ans.append(Fr(1, ceil(1/fr)))
fr = Fr(-y % x, y* ceil(1/fr))
x, y = fr.numerator, fr.denominator
ans.append(fr)
return ans

if __name__ == '__main__':
for fr in [Fr(43, 48), Fr(5, 121), Fr(2014, 59)]:
print('%r ─► %s' % (fr, ' '.join(str(x) for x in ef(fr))))
lenmax = denommax = (0, None)
for fr in set(Fr(a, b) for a in range(1,100) for b in range(1, 100)):
e = ef(fr)
#assert sum((f[0] if type(f) is list else f) for f in e) == fr, 'Whoops!'
elen, edenom = len(e), e[-1].denominator
if elen > lenmax[0]:
lenmax = (elen, fr, e)
if edenom > denommax[0]:
denommax = (edenom, fr, e)
print('Term max is %r with %i terms' % (lenmax[1], lenmax[0]))
dstr = str(denommax[0])
print('Denominator max is %r with %i digits %s...%s' %
(denommax[1], len(dstr), dstr[:5], dstr[-5:]))

Output:
43/48 ─► 1/2 1/3 1/16
5/121 ─► 1/25 1/757 1/763309 1/873960180913 1/1527612795642093418846225
2014/59 ─► [34] 1/8 1/95 1/14947 1/670223480
Term max is 97/53 with 9 terms
Denominator max is 8/97 with 150 digits 57950...89665

### Composition of pure functions

The derivation of a sequence of unit fractions from a single fraction is a classic case of an anamorphism or unfold abstraction – dual to a fold or catamorphism. Rather than reducing, collapsing or summarizing a structure to a single value, it builds a structure from a single value.

See the unfoldr function below:

Works with: Python version 3.7
'''Egyptian fractions'''

from fractions import Fraction
from functools import reduce
from operator import neg

# eqyptianFraction :: Ratio Int -> Ratio Int
def eqyptianFraction(nd):
'''The rational number nd as a sum
of the series of unit fractions
obtained by application of the
greedy algorithm.'''
def go(x):
n, d = x.numerator, x.denominator
r = 1 + d // n if n else None
return Just((0, x) if 1 == n else (
(fr(n % d, d), fr(n // d, 1)) if n > d else (
fr(-d % n, d * r), fr(1, r)
)
)) if n else Nothing()
fr = Fraction
f = unfoldr(go)
return list(map(neg, f(-nd))) if 0 > nd else f(nd)

# TESTS ---------------------------------------------------

# maxEqyptianFraction :: Int -> (Ratio Int -> a)
#                               -> (Ratio Int, a)
def maxEqyptianFraction(nDigits):
'''An Egyptian Fraction, representing a
proper fraction with numerators and
denominators of up to n digits each,
which returns a maximal value for the
supplied function f.'''

# maxVals :: ([Ratio Int], a) -> (Ratio Int, a)
#                               -> ([Ratio Int], a)
def maxima(xsv, ndfx):
xs, v = xsv
nd, fx = ndfx
return ([nd], fx) if fx > v else (
xs + [nd], v
) if fx == v and nd not in xs else xsv

# go :: (Ratio Int -> a) -> ([Ratio Int], a)
def go(f):
iLast = int(nDigits * '9')
fs, mx = reduce(
maxima, [
(nd, f(eqyptianFraction(nd))) for nd in [
Fraction(n, d)
for n in enumFromTo(1)(iLast)
for d in enumFromTo(1 + n)(iLast)
]
],
([], 0)
)
return f.__name__ + ' -> [' + ', '.join(
map(str, fs)
) + '] -> ' + str(mx)
return lambda f: go(f)

# main :: IO ()
def main():
'''Tests'''

ef = eqyptianFraction
fr = Fraction

print('Three values as Eqyptian fractions:')
print('\n'.join([
str(fr(*nd)) + ' -> ' + ' + '.join(map(str, ef(fr(*nd))))
for nd in [(43, 48), (5, 121), (2014, 59)]
]))

# maxDenominator :: [Ratio Int] -> Int
def maxDenominator(ef):
return max(map(lambda nd: nd.denominator, ef))

# maxTermCount :: [Ratio Int] -> Int
def maxTermCount(ef):
return len(ef)

for i in [1, 2, 3]:
print(
'\nMaxima for proper fractions with up to ' + (
str(i) + ' digit(s):'
)
)
for f in [maxTermCount, maxDenominator]:
print(maxEqyptianFraction(i)(f))

# GENERIC -------------------------------------------------

# Just :: a -> Maybe a
def Just(x):
'''Constructor for an inhabited Maybe (option type) value.'''
return {'type': 'Maybe', 'Nothing': False, 'Just': x}

# Nothing :: Maybe a
def Nothing():
'''Constructor for an empty Maybe (option type) value.'''
return {'type': 'Maybe', 'Nothing': True}

# enumFromTo :: (Int, Int) -> [Int]
def enumFromTo(m):
'''Integer enumeration from m to n.'''
return lambda n: list(range(m, 1 + n))

# unfoldr :: (b -> Maybe (b, a)) -> b -> [a]
def unfoldr(f):
'''Dual to reduce or foldr.
Where catamorphism reduces a list to a summary value,
the anamorphic unfoldr builds a list from a seed value.
As long as f returns Just(a, b), a is prepended to the list,
and the residual b is used as the argument for the next
application of f.
When f returns Nothing, the completed list is returned.'''
def go(xr):
mb = f(xr[0])
if mb.get('Nothing'):
return []
else:
y, r = mb.get('Just')
return [r] + go((y, r))

return lambda x: go((x, x))

# MAIN ---
if __name__ == '__main__':
main()

Output:
Three values as Eqyptian fractions:
43/48 -> 1/2 + 1/3 + 1/16
5/121 -> 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225
2014/59 -> 34 + 1/8 + 1/95 + 1/14947 + 1/670223480

Maxima for proper fractions with up to 1 digit(s):
maxTermCount -> [3/7, 4/5, 5/7, 6/7, 7/8, 7/9, 8/9] -> 3
maxDenominator -> [3/7] -> 231

Maxima for proper fractions with up to 2 digit(s):
maxTermCount -> [8/97, 44/53] -> 8
maxDenominator -> [8/97] -> 579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665

Maxima for proper fractions with up to 3 digit(s):
maxTermCount -> [529/914, 641/796] -> 13
maxDenominator -> [36/457, 529/914] -> 839018826833450186636781520007011999269820404906753180244759299287837378895397605613261469995626498719289835112392530430840514102146998625666594756995273418015600023494049208108894185781774002683063204252356172520941088783702738286944210460710059319691268110283467445381026653628599765684739105388642310044785844902157076919003735231543781785073393176144167688252446541416466418608465458502997971425428342769433127784560570193376772878336217849260872114137931351960543608384244009505664253173875705234889570853924105640193619301332776989688248555027054395237907581951261868280899150574360164800187964167274323078311078867593844043149124596271281252530924719121766925749760855109100066731841478262812686642693395896229983745226277793055820609058348269152190083695704685769622011655159174272326647342695589818127126303038171968768650476413027459205291075571637957597356820188031655122749743652301268394542123970892422944335857917641636041892192547135178153602038877677614358281581103685526041329841496863410305888255234495015115912388514981113593387572720476744188169200130515719608747338810136728267784013352396910979904545913458536243327311977805126410065576961237640824852114328884086581542091492600312838425666927627674227053793897767395465326589843035773944346372949759909905561209334216847158156644884281300512699910530092870919061876615770708519243818676366245477462042294267674677954783726990349386117468071932874021023714524610740225814235147693954027910741673103980749749728106483987721602738673173009362802337092908847797499475895347112889339502928407808058670297722175686638678788738689803945574002805677250463286479363670076942509109589495377221095405979217163821481666646160815221224686562530536116613645305335922819524037829878961518170177968768364853399057357772141655622381280196908637031556436461404285930426436983658106288733881761514992109680298995922754466040011586713812553117621857109517258943846004179432521131844156242428351270188803919554398620084668514054504414062276012292497375238210886595006249453460414790147611422121782194848803348777061816460876697945418158442269512987729152441940326466631610424906158237288218706447963113019239557885486647314085357651895226117364760315394354624547919209138539180807829672545924239541758108877100331729470119526373928796447673951888289511964811633025369821156695934557103429921063387965046715070102916811976552584464153981214277622597308113449320462341683055200576571910241686615924531368198770946893858410058348221985603151428153382461711196734214085852523778422630907646235900752317571022131569421231196329080023952364788544301495422061066036911772385739659997665503832444529713544286955548310166168837889046149061296461059432238621602179724809510024772127497080258401694929973105184832214622785679651550368465524821062859837409907538269572622296774545103747438431266995525592705

## Racket

#lang racket
(define (real->egyptian-list R)
(define (inr r rv)
(match* ((exact-floor r) (numerator r) (denominator r))
[(0 0 1) (reverse rv)]
[(0 1 d) (reverse (cons (/ d) rv))]
[(0 x y) (let ((^y/x (exact-ceiling (/ y x))))
(inr (/ (modulo (- y) x) (* y ^y/x)) (cons (/ ^y/x) rv)))]
[(flr _ _) (inr (- r flr) (cons flr rv))]))
(inr R null))

(define (real->egyptian-string f)
(define e.f.-list (real->egyptian-list f))
(define fmt-part
(match-lambda
[(? integer? (app number->string s)) s]
[(app (compose number->string /) s) (format "/~a"s)]))
(string-join (map fmt-part e.f.-list) " + "))

(define (stat-egyptian-fractions max-b+1)
(define-values (max-l max-l-f max-d max-d-f)
(for*/fold ((max-l 0) (max-l-f #f) (max-d 0) (max-d-f #f))
((b (in-range 1 max-b+1)) (a (in-range 1 b)) #:when (= 1 (gcd a b)))
(define f (/ a b))
(define e.f (real->egyptian-list (/ a b)))
(define l (length e.f))
(define d (denominator (last e.f)))
(values (max max-l l) (if (> l max-l) f max-l-f)
(max max-d d) (if (> d max-d) f max-d-f))))
(printf #<<EOS
max #terms: ~a has ~a
[~.a]
max denominator: ~a has ~a
[~.a]

EOS
max-l-f max-l (real->egyptian-string max-l-f)
max-d-f max-d (real->egyptian-string max-d-f)))

(displayln (real->egyptian-string 43/48))
(displayln (real->egyptian-string 5/121))
(displayln (real->egyptian-string 2014/59))
(newline)
(stat-egyptian-fractions 100)
(newline)
(stat-egyptian-fractions 1000)

(module+ test (require tests/eli-tester)
(test (real->egyptian-list 43/48) => '(1/2 1/3 1/16)))

Output:

(Line continuations have been manually added to this "post-production")

/2 + /3 + /16
/25 + /757 + /763309 + /873960180913 + /1527612795642093418846225
34 + /8 + /95 + /14947 + /670223480

max #terms: 44/53 has 8
[/2 + /4 + /13 + /307 + /120871 + /20453597227 + /697249399186783218655 + /1458\
470173998990524806872692984177836808420]
max denominator: 8/97 has 57950458706754280171310319185991860825103029195219542\
3583529357653899418686342360361798689053273749372615043661810228371898539583862\
011424993909789665
[/13 + /181 + /38041 + /1736503177 + /3769304102927363485 + /189435378937934085\
04192074528154430149 + /5382864419003802113658172851049070863474397461302269732\
53778132494225813153 + /5795045870675428017131031918599186082510302919521954235\
83529357653...]

max #terms: 641/796 has 13
[/2 + /4 + /19 + /379 + /159223 + /28520799973 + /929641178371338400861 + /1008\
271507277592391123742528036634174730681 + /121993371886539365536463536806812475\
6713122928811333803786753398211072842948484537833 + /18602978480309366547426083\
99135821395...]
max denominator: 36/457 has 839018826833450186636781520007011999269820404906753\
1802447592992878373788953976056132614699956264987192898351123925304308405141021\
4699862566659475699527341801560002349404920810889418578177400268306320425235617\
2520941088783702738286944210460710059319691268110283467445381026653628599765684\
7391053886423100447858449021570769190037352315437817850733931761441676882524465\
4141646641860846545850299797142542834276943312778456057019337677287833621784926\
0872114137931351960543608384244009505664253173875705234889570853924105640193619\
3013327769896882485550270543952379075819512618682808991505743601648001879641672\
7432307831107886759384404314912459627128125253092471912176692574976085510910006\
6731841478262812686642693395896229983745226277793055820609058348269152190083695\
7046857696220116551591742723266473426955898181271263030381719687686504764130274\
5920529107557163795759735682018803165512274974365230126839454212397089242294433\
5857917641636041892192547135178153602038877677614358281581103685526041329841496\
8634103058882552344950151159123885149811135933875727204767441881692001305157196\
0874733881013672826778401335239691097990454591345853624332731197780512641006557\
6961237640824852114328884086581542091492600312838425666927627674227053793897767\
3954653265898430357739443463729497599099055612093342168471581566448842813005126\
9991053009287091906187661577070851924381867636624547746204229426767467795478372\
6990349386117468071932874021023714524610740225814235147693954027910741673103980\
7497497281064839877216027386731730093628023370929088477974994758953471128893395\
0292840780805867029772217568663867878873868980394557400280567725046328647936367\
0076942509109589495377221095405979217163821481666646160815221224686562530536116\
6136453053359228195240378298789615181701779687683648533990573577721416556223812\
8019690863703155643646140428593042643698365810628873388176151499210968029899592\
2754466040011586713812553117621857109517258943846004179432521131844156242428351\
2701888039195543986200846685140545044140622760122924973752382108865950062494534\
6041479014761142212178219484880334877706181646087669794541815844226951298772915\
2441940326466631610424906158237288218706447963113019239557885486647314085357651\
8952261173647603153943546245479192091385391808078296725459242395417581088771003\
3172947011952637392879644767395188828951196481163302536982115669593455710342992\
1063387965046715070102916811976552584464153981214277622597308113449320462341683\
0552005765719102416866159245313681987709468938584100583482219856031514281533824\
6171119673421408585252377842263090764623590075231757102213156942123119632908002\
3952364788544301495422061066036911772385739659997665503832444529713544286955548\
3101661688378890461490612964610594322386216021797248095100247721274970802584016\
9492997310518483221462278567965155036846552482106285983740990753826957262229677\
4545103747438431266995525592705
[/13 + /541 + /321409 + /114781617793 + /14821672255960844346913 + /25106510681\
4993628596500876449600804290086881 + /73539302503361520198362339236500915390885\
795679264404865887253300925727812630083326272641 + /648963481521709674175890714\
89823812369...]
1 test passed

## Raku

(formerly Perl 6)

role Egyptian {
method gist {
join ' + ',
("[{self.floor}]" if self.abs >= 1),
map {"1/$_"}, self.denominators; } method denominators { my ($x, $y) = self.nude;$x %= $y; my @denom = gather ($x, $y) = -$y % $x,$y * take ($y /$x).ceiling
while $x; } } say .nude.join('/'), " = ",$_ but Egyptian for 43/48, 5/121, 2014/59;

my @sample = map { $_ => .denominators }, grep * < 1, map {$_ but Egyptian},
(2 .. 99 X/ 2 .. 99);

say .key.nude.join("/"),
" has max denominator, namely ",
.value.max
given max :by(*.value.max), @sample;

say .key.nude.join("/"),
" has max number of denominators, namely ",
.value.elems
given max :by(*.value.elems), @sample;

Output:
43/48 = 1/2 + 1/3 + 1/16
5/121 = 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225
2014/59 = [34] + 1/8 + 1/95 + 1/14947 + 1/670223480
8/97 has max denominator, namely 579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665
8/97 has max number of denominators, namely 8

Because the harmonic series diverges (albeit very slowly), it is possible to write even improper fractions as a sum of distinct unit fractions. Here is a code to do that:

role Egyptian {
method gist { join ' + ', map {"1/$_"}, self.list } method list { my$sum = 0;
gather for 2 .. * {
last if $sum == self;$sum += 1 / .take unless $sum + 1 /$_ > self;
}
}
}

say 5/4 but Egyptian;

Output:
1/2 + 1/3 + 1/4 + 1/6

The list of terms grows exponentially with the value of the fraction, though.

## REXX

/*REXX program converts a fraction (can be improper) to an Egyptian fraction. */
parse arg fract '' -1 t;  z=$egyptF(fract) /*compute the Egyptian fraction. */ if t\==. then say fract ' ───► ' z /*show Egyptian fraction from C.L.*/ return z /*stick a fork in it, we're done.*/ /*────────────────────────────────$EGYPTF subroutine──────────────────────────*/
$egyptF: parse arg z 1 zn '/' zd,,$;   if zd==''  then zd=1   /*whole number ?*/
if z=''               then call erx  "no fraction was specified."
if zd==0              then call erx  "denominator can't be zero:"       zd
if zn==0              then call erx  "numerator can't be zero:"         zn
if zd<0 | zn<0        then call erx  "fraction can't be negative"       z
if \datatype(zn,'W')  then call erx  "numerator must be an integer:"    zn
if \datatype(zd,'W')  then call erx  "denominator must be an integer:"  zd
_=zn%zd                                /*check if it's an improper fraction.  */
if _>=1  then do                       /*if improper fraction, then append it.*/
$='['_"]" /*append the whole # part of fraction. */ zn=zn-_*zd /*now, just use the proper fraction. */ if zn==0 then return$  /*Is there no fraction? Then we're done*/
end
if zd//zn==0  then do;  zd=zd%zn;  zn=1;  end
do  forever
if zn==1 & datatype(zd,'W')  then return $"1/"zd /*append Egyptian fract.*/ nd=zd%zn+1;$=$'1/'nd /*add unity to integer fraction, append*/ z=$fractSub(zn'/'zd,  "-",  1'/'nd)  /*go and subtract the two fractions.   */
parse var z zn '/' zd                /*extract the numerator and denominator*/
L=2*max(length(zn),length(zd))       /*calculate if need more decimal digits*/
if L>=digits()  then numeric digits L+L  /*yes, then bump the decimal digits*/
end   /*forever*/                    /* [↑]  the DO forever ends when zn==1.*/
/*────────────────────────────────$FRACTSUB subroutine────────────────────────*/$fractSub: procedure;  parse arg z.1,,z.2 1 zz.2;  arg ,op
do j=1  for 2;    z.j=translate(z.j,'/',"_");   end
if z.1==''  then z.1=(op\=="+" & op\=='-')     /*unary +,-     first fraction.*/
if z.2==''  then z.2=(op\=="+" & op\=='-')     /*unary +.-    second fraction.*/
do j=1  for 2                                /*process both of the fractions*/
if pos('/',z.j)==0     then z.j=z.j"/1";     parse var  z.j  n.j  '/'  d.j
if \datatype(n.j,'N')  then call erx  "numerator isn't an integer:"    n.j
if \datatype(d.j,'N')  then call erx  "denominator isn't an integer:"  d.j
n.j=n.j/1;   d.j=d.j/1                    /*normalize numerator/denominator.*/

do  while \datatype(n.j,'W');  n.j=n.j*10/1;  d.j=d.j*10/1;  end /*while*/
/* [↑]  normalize both numbers.   */
if d.j=0  then call erx  "denominator can't be zero:"   z.j
g=gcd(n.j,d.j);   if g=0  then iterate;     n.j=n.j/g;         d.j=d.j/g
end    /*j*/
l=lcm(d.1 d.2);             do j=1  for 2;  n.j=l*n.j/d.j;  d.j=l;  end  /*j*/
if op=='-'  then n.2=-n.2
t=n.1+n.2;       u=l;                  if t==0  then return 0
g=gcd(t,u);      t=t/g;     u=u/g;     if u==1  then return t
return t'/'u
/*─────────────────────────────general 1─line subs────────────────────────────*/
erx:  say;  say '***error!***' arg(1);       say;          exit 13
gcd:procedure;$=;do i=1 for arg();$=$arg(i);end;parse var$ x z .;if x=0 then x=z;x=abs(x);do j=2 to words($);y=abs(word($,j));if y=0 then iterate;do until _==0;_=x//y;x=y;y=_;end;end;return x
lcm:procedure;y=;do j=1 for arg();y=y arg(j);end;x=word(y,1);do k=2 to words(y);!=abs(word(y,k));if !=0 then return 0;x=x*!/gcd(x,!);end;return x
p:  return word(arg(1),1)


output   when the input used is:   43/48


43/48  ───►   1/2 1/3 1/16


output when the input used is:   5/121

5/121  ───►   1/25 1/757 1/763309 1/873960180913 1/1527612795642093418846225


output when the input used is:   2014/59

2014/59  ───►   [34] 1/8 1/95 1/14947 1/670223480


The following is a driver program to address the requirements to find the largest number of terms for a
1- or 2-digit integer, and the largest denominator.

Also, the same program is used for the 1-, 2-, and 3-digit extra credit task.

/*REXX pgm runs the EGYPTIAN program to find biggest denominator & # of terms.*/
parse arg top .                        /*get optional parameter from the C.L. */
if top==''  then top=99                /*Not specified?  Then use the default.*/
oTop=top;   top=abs(top)               /*oTop used as a flag to display maxD. */
maxT=0;     maxD=0;     bigD=;   bigT= /*initialize some REXX variables.      */
/* [↓]  determine biggest andlongest.  */
do n=2      to top               /*traipse through the  numerators.     */
do d=n+1  to top             /*   "       "     "  denominators     */
fract=n'/'d                  /*create the fraction to be used.      */
y='EGYPTIAN'(fract||.)       /*invoke the REXX program  EGYPTIAN.REX*/
t=words(y)                   /*number of terms in Egyptian fraction.*/
if t>maxT  then bigT=fract   /*is this a new high for number terms? */
maxT=max(maxT,T)             /*find the maximum number of terms.    */
b=substr(word(y,t),3)        /*get denominator from Egyptian fract. */
if b>maxD  then bigD=fract   /*is this a new denominator high ?     */
maxD=max(maxD,b)             /*find the maximum denominator.        */
end   /*d*/                  /* [↑]  only use proper fractions.     */
end       /*n*/                  /* [↑]  ignore the   1/n   fractions.  */
/* [↑]  display the longest and biggest*/
@= 'in the Egyptian fractions used is' /*literal is used to make a shorter SAY*/
say 'largest number of terms'  @   maxT   "terms for"   bigT
say
say 'highest denominator'      @   length(maxD)   "digits for"  bigD
if oTop>0  then say maxD               /*stick a fork in it,  we're all done. */


output   for all 1- and 2-digit integers when using the default input:

largest number of terms in the Egyptian fractions used is 8 terms for 8/97
largest denominator in the Egyptian fractions is 150 digits is for 8/97
579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665


output   for all 1-, 2-, and 3-digit integers when using for input:   -999

largest number of terms in the Egyptian fractions used is 13 terms for 529/914
largest denominator in the Egyptian fractions is 2847 digits is for 36/457


## RPL

GCD is defined at Greatest common divisor

Works with: Halcyon Calc version 4.2.7
RPL code Comment
  ≪
DUP IM LAST RE / CEIL
SWAP RE LAST IM DUP NEG ROT MOD
SWAP 3 PICK *
DUP2 GCD ROT OVER / ROT ROT / R→C
≫ 'SPLIT' STO

≪
DUP 3 EXGET SWAP 1 EXGET
IF DUP2 > THEN
SWAP OVER MOD LAST / IP SWAP ROT
ELSE 0 ROT ROT END
R→C
WHILE DUP RE REPEAT
SPLIT
"'1/" ROT →STR + "'" + STR→
ROT SWAP + SWAP
END
≫ 'EGYPF' STO

SPLIT ( (x1,y1) → n1 (x2,y2) )
n1 = ceil(y1/x1)
x2 = mod(-y1,x1)
y2 = n1*y1
simplify x2/y2

EGYPF ( 'x/y' → 'sum_of_Egyptian_fractions')
put x and y in stack
if x > y
first term of sum is x//y and x = mod(x,y)
else first term is 0
convert to complex to ease handling in stack
loop while xk ≠ 0
get nk and (xk, yk)
convert nk into '1/nk'
add '1/nk' to the sum
end loop
return sum

'43/48' EGYPF
'5/121' EGYPF
'2014/59' EGYPF

Output:
3: 'INV(2)+INV(3)+INV(16)'
2: 'INV(25)+INV(757)+INV(763309)+INV(873960180913)+INV(1.52761279564E+24)'
1: '34+INV(8)+INV(95)+INV(14947)+INV(670223480)'


In algebraic expressions, RPL automatically replaces 1/n by INV(n)

#### Quest for the largest number of items for proper fractions 2.99/2..99

≪ '1/1' 0
2 99 FOR d 2 d 1 - FOR n
"'" n →STR + "/" + d →STR + "'" + STR→
DUP EGYPF SIZE → f sf
≪ IF sf OVER > THEN DROP2 f sf END ≫
NEXT NEXT DROP

Output:
1: '44/53'


Limited precision of basic RPL prevents from searching the largest denominator.

## Ruby

Translation of: Python
def ef(fr)
ans = []
if fr >= 1
return [[fr.to_i], Rational(0, 1)]  if fr.denominator == 1
intfr = fr.to_i
ans, fr = [intfr], fr - intfr
end
x, y = fr.numerator, fr.denominator
while x != 1
ans << Rational(1, (1/fr).ceil)
fr = Rational(-y % x, y * (1/fr).ceil)
x, y = fr.numerator, fr.denominator
end
ans << fr
end

for fr in [Rational(43, 48), Rational(5, 121), Rational(2014, 59)]
puts '%s => %s' % [fr, ef(fr).join(' + ')]
end

lenmax = denommax = [0]
for b in 2..99
for a in 1...b
fr = Rational(a,b)
e = ef(fr)
elen, edenom = e.length, e[-1].denominator
lenmax = [elen, fr] if elen > lenmax[0]
denommax = [edenom, fr] if edenom > denommax[0]
end
end
puts 'Term max is %s with %i terms' % [lenmax[1], lenmax[0]]
dstr = denommax[0].to_s
puts 'Denominator max is %s with %i digits' % [denommax[1], dstr.size], dstr

Output:
43/48 => 1/2 + 1/3 + 1/16
5/121 => 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225
2014/59 => 34 + 1/8 + 1/95 + 1/14947 + 1/670223480
Term max is 44/53 with 8 terms
Denominator max is 8/97 with 150 digits
579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665


## Rust

use num_bigint::BigInt;
use num_integer::Integer;
use num_traits::{One, Zero};
use std::fmt;

#[derive(Debug, Clone, PartialEq, PartialOrd)]
struct Rational {
nominator: BigInt,
denominator: BigInt,
}

impl Rational {
fn new(n: &BigInt, d: &BigInt) -> Rational {
assert!(!d.is_zero(), "denominator cannot be 0");
// simplify if possible
let c = n.gcd(d);
Rational {
nominator: n / &c,
denominator: d / &c,
}
}

fn is_proper(&self) -> bool {
self.nominator < self.denominator
}
fn to_egyptian(&self) -> Vec<Rational> {
let mut frac: Vec<Rational> = Vec::new();

let mut current: Rational;
if !self.is_proper() {
// input is grater than 1
// store the integer part
frac.push(Rational::new(
&self.nominator.div_floor(&self.denominator),
&One::one(),
));

// calculate the remainder
current = Rational::new(
&self.nominator.mod_floor(&self.denominator),
&self.denominator,
);
} else {
current = self.clone();
}

while !current.nominator.is_one() {
let div = current.denominator.div_ceil(&current.nominator);

// store the term
frac.push(Rational::new(&One::one(), &div));

current = Rational::new(
&(-&current.denominator).mod_floor(&current.nominator),
match current.denominator.checked_mul(&div).as_ref() {
Some(r) => r,
_ => break,
},
);
}

frac.push(current);
frac
}
}

impl fmt::Display for Rational {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
if self.denominator.is_one() {
// for integers only display the integer part
write!(f, "{}", self.nominator)
} else {
write!(f, "{}/{}", self.nominator, self.denominator)
}
}
}

fn rational_vec_to_string(vec: Vec<Rational>) -> String {
let mut p = vec
.iter()
.fold(String::new(), |acc, num| (acc + &num.to_string() + ", "));

if p.len() > 1 {
p.truncate(p.len() - 2);
}
format!("[{}]", p)
}

fn run_max_searches(x: usize) {
// generate all proper fractions with 2 digits
let pairs = (1..x).flat_map(move |i| (i + 1..x).map(move |j| (i, j)));

let mut max_length = (0, Rational::new(&BigInt::from(1), &BigInt::from(1)));
let mut max_denom = (
Zero::zero(),
Rational::new(&BigInt::from(1), &BigInt::from(1)),
);

for (i, j) in pairs {
let e = Rational::new(&BigInt::from(i), &BigInt::from(j)).to_egyptian();
if e.len() > max_length.0 {
max_length = (e.len(), Rational::new(&BigInt::from(i), &BigInt::from(j)));
}

if e.last().unwrap().denominator > max_denom.0 {
max_denom = (
e.last().unwrap().denominator.clone(),
Rational::new(&BigInt::from(i), &BigInt::from(j)),
);
}
}

println!(
"Maximum length of terms is for {} with {} terms",
max_length.1, max_length.0
);
println!("{}", rational_vec_to_string(max_length.1.to_egyptian()));

println!(
"Maximum denominator is for {} with {} terms",
max_denom.1, max_denom.0
);
println!("{}", rational_vec_to_string(max_denom.1.to_egyptian()));
}
fn main() {
let tests = [
Rational::new(&BigInt::from(43), &BigInt::from(48)),
Rational::new(&BigInt::from(5), &BigInt::from(121)),
Rational::new(&BigInt::from(2014), &BigInt::from(59)),
];

for test in tests.iter() {
println!("{} -> {}", test, rational_vec_to_string(test.to_egyptian()));
}

run_max_searches(100);
run_max_searches(1000);
}

Output:
43/48 -> [1/2, 1/3, 1/16]
5/121 -> [1/25, 1/757, 1/763309, 1/873960180913, 1/1527612795642093418846225]
2014/59 -> [34, 1/8, 1/95, 1/14947, 1/670223480]
Maximum length of terms is for 8/97 with 8 terms
[1/13, 1/181, 1/38041, 1/1736503177, 1/3769304102927363485, 1/18943537893793408504192074528154430149, 1/538286441900380211365817285104907086347439746130226973253778132494225813153, 1/579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665]
Maximum denominator is for 8/97 with 5795045870675428017131...3909789665 terms (150 digits)
[1/13, 1/181, 1/38041, 1/1736503177, 1/3769304102927363485, 1/18943537893793408504192074528154430149, 1/538286441900380211365817285104907086347439746130226973253778132494225813153, 1/5795045870675428017131...3909789665]
Maximum length of terms is for 529/914 with 13 terms:
[1/2, 1/13, 1/541, 1/321409, 1/114781617793, 1/14821672255960844346913, 1/251065106814993628596500876449600804290086881, 1/73539302503361520198362339236500915390885795679264404865887253300925727812630083326272641, 1/6489634815217096741...91865217, 1/52644200043...5476206145, 1/36952157309...38141889, 1/204819289476534...06590593, 1/83901882683...25592705]
Maximum denominator is for 36/457 with 83901882683...25592705 (2847 digits)


## Scala

Translation of: Java
import scala.annotation.tailrec
import scala.collection.mutable
import scala.collection.mutable.{ArrayBuffer, ListBuffer}

abstract class Frac extends Comparable[Frac] {
val num: BigInt
val denom: BigInt

def toEgyptian: List[Frac] = {
if (num == 0) {
return List(this)
}

val fracs = new ArrayBuffer[Frac]
if (num.abs >= denom.abs) {
val div = Frac(num / denom, 1)
val rem = this - div
fracs += div
egyptian(rem.num, rem.denom, fracs)
} else {
egyptian(num, denom, fracs)
}
fracs.toList
}

@tailrec
private def egyptian(n: BigInt, d: BigInt, fracs: mutable.Buffer[Frac]): Unit = {
if (n == 0) {
return
}
val n2 = BigDecimal.apply(n)
val d2 = BigDecimal.apply(d)
val (divbd, rembd) = d2./%(n2)
var div = divbd.toBigInt()
if (rembd > 0) {
div = div + 1
}
fracs += Frac(1, div)
var n3 = -d % n
if (n3 < 0) {
n3 = n3 + n
}
val d3 = d * div
val f = Frac(n3, d3)
if (f.num == 1) {
fracs += f
return
}
egyptian(f.num, f.denom, fracs)
}

def unary_-(): Frac = {
Frac(-num, denom)
}

def +(rhs: Frac): Frac = {
Frac(
num * rhs.denom + rhs.num * denom,
denom * rhs.denom
)
}

def -(rhs: Frac): Frac = {
Frac(
num * rhs.denom - rhs.num * denom,
denom * rhs.denom
)
}

override def compareTo(rhs: Frac): Int = {
val ln = num * rhs.denom
val rn = rhs.num * denom
ln.compare(rn)
}

def canEqual(other: Any): Boolean = other.isInstanceOf[Frac]

override def equals(other: Any): Boolean = other match {
case that: Frac =>
(that canEqual this) &&
num == that.num &&
denom == that.denom
case _ => false
}

override def hashCode(): Int = {
val state = Seq(num, denom)
state.map(_.hashCode()).foldLeft(0)((a, b) => 31 * a + b)
}

override def toString: String = {
if (denom == 1) {
return s"$num" } s"$num/$denom" } } object Frac { def apply(n: BigInt, d: BigInt): Frac = { if (d == 0) { throw new IllegalArgumentException("Parameter d may not be zero.") } var nn = n var dd = d if (nn == 0) { dd = 1 } else if (dd < 0) { nn = -nn dd = -dd } val g = nn.gcd(dd) if (g > 0) { nn /= g dd /= g } new Frac { val num: BigInt = nn val denom: BigInt = dd } } } object EgyptianFractions { def main(args: Array[String]): Unit = { val fracs = List.apply( Frac(43, 48), Frac(5, 121), Frac(2014, 59) ) for (frac <- fracs) { val list = frac.toEgyptian val it = list.iterator print(s"$frac -> ")
if (it.hasNext) {
val value = it.next()
if (value.denom == 1) {
print(s"[$value]") } else { print(value) } } while (it.hasNext) { val value = it.next() print(s" +$value")
}
println()
}

for (r <- List(98, 998)) {
println()
if (r == 98) {
println("For proper fractions with 1 or 2 digits:")
} else {
println("For proper fractions with 1, 2 or 3 digits:")
}

var maxSize = 0
var maxSizeFracs = new ListBuffer[Frac]
var maxDen = BigInt(0)
var maxDenFracs = new ListBuffer[Frac]
val sieve = Array.ofDim[Boolean](r + 1, r + 2)
for (i <- 0 until r + 1) {
for (j <- i + 1 until r + 1) {
if (!sieve(i)(j)) {
val f = Frac(i, j)
val list = f.toEgyptian
val listSize = list.size
if (listSize > maxSize) {
maxSize = listSize
maxSizeFracs.clear()
maxSizeFracs += f
} else if (listSize == maxSize) {
maxSizeFracs += f
}
val listDen = list.last.denom
if (listDen > maxDen) {
maxDen = listDen
maxDenFracs.clear()
maxDenFracs += f
} else if (listDen == maxDen) {
maxDenFracs += f
}
if (i < r / 2) {
var k = 2
while (j * k <= r + 1) {
sieve(i * k)(j * k) = true
k = k + 1
}
}
}
}
}
println(s"  largest number of items = $maxSize") println(s"fraction(s) with this number :${maxSizeFracs.toList}")
val md = maxDen.toString()
print(s"  largest denominator = ${md.length} digits, ") println(s"${md.substring(0, 20)}...${md.substring(md.length - 20)}") println(s"fraction(s) with this denominator :${maxDenFracs.toList}")
}
}
}

Output:
43/48 -> 1/2 + 1/3 + 1/16
5/121 -> 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225
2014/59 -> [34] + 1/8 + 1/95 + 1/14947 + 1/670223480

For proper fractions with 1 or 2 digits:
largest number of items = 8
fraction(s) with this number : List(8/97, 44/53)
largest denominator = 150 digits, 57950458706754280171...62011424993909789665
fraction(s) with this denominator : List(8/97)

For proper fractions with 1, 2 or 3 digits:
largest number of items = 13
fraction(s) with this number : List(529/914, 641/796)
largest denominator = 2847 digits, 83901882683345018663...38431266995525592705
fraction(s) with this denominator : List(36/457, 529/914)

## Sidef

Translation of: Ruby
func ef(fr) {
var ans = []
if (fr >= 1) {
return([fr]) if (fr.is_int)
var intfr = fr.int
ans << intfr
fr -= intfr
}
var (x, y) = fr.nude
while (x != 1) {
ans << fr.inv.ceil.inv
fr = ((-y % x) / y*fr.inv.ceil)
(x, y) = fr.nude
}
ans << fr
return ans
}

for fr in [43/48, 5/121, 2014/59] {
"%s => %s\n".printf(fr.as_rat, ef(fr).map{.as_rat}.join(' + '))
}

var lenmax = (var denommax = [0])
for b in range(2, 99) {
for a in range(1, b-1) {
var fr = a/b
var e = ef(fr)
var (elen, edenom) = (e.length, e[-1].denominator)
lenmax = [elen, fr] if (elen > lenmax[0])
denommax = [edenom, fr] if (edenom > denommax[0])
}
}

"Term max is %s with %i terms\n".printf(lenmax[1].as_rat, lenmax[0])
"Denominator max is %s with %i digits\n".printf(denommax[1].as_rat, denommax[0].size)
say denommax[0]

Output:
43/48 => 1/2 + 1/3 + 1/16
5/121 => 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225
2014/59 => 34 + 1/8 + 1/95 + 1/14947 + 1/670223480
Term max is 44/53 with 8 terms
Denominator max is 8/97 with 150 digits
579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665


## Tcl

# Just compute the denominator terms, as the numerators are always 1
proc egyptian {num denom} {
set result {}
while {$num} { # Compute ceil($denom/$num) without floating point inaccuracy set term [expr {$denom / $num + ($denom/$num*$num < $denom)}] lappend result$term
set num [expr {-$denom %$num}]
set denom [expr {$denom *$term}]
}
return $result }  Demonstrating: Works with: Tcl version 8.6 package require Tcl 8.6 proc efrac {fraction} { scan$fraction "%d/%d" x y
set prefix ""
if {$x >$y} {
set whole [expr {$x /$y}]
set x [expr {$x -$whole*$y}] set prefix "$whole$ + " } return$prefix[join [lmap y [egyptian $x$y] {format "1/%lld" $y}] " + "] } foreach f {43/48 5/121 2014/59} { puts "$f = [efrac $f]" } set maxt 0 set maxtf {} set maxd 0 set maxdf {} for {set d 1} {$d < 100} {incr d} {
for {set n 1} {$n <$d} {incr n} {
set e [egyptian $n$d]
if {[llength $e] >=$maxt} {
set maxt [llength $e] set maxtf$n/$d } if {[lindex$e end] > $maxd} { set maxd [lindex$e end]
set maxdf $n/$d
}
}
}
puts "$maxtf has maximum number of terms = [efrac$maxtf]"
puts "$maxdf has maximum denominator = [efrac$maxdf]"

Output:
43/48 = 1/2 + 1/3 + 1/16
5/121 = 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225
2014/59 = [34] + 1/8 + 1/95 + 1/14947 + 1/670223480
8/97 has maximum number of terms = 1/13 + 1/181 + 1/38041 + 1/1736503177 + 1/3769304102927363485 + 1/18943537893793408504192074528154430149 + 1/538286441900380211365817285104907086347439746130226973253778132494225813153 + 1/579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665
8/97 has maximum denominator = 1/13 + 1/181 + 1/38041 + 1/1736503177 + 1/3769304102927363485 + 1/18943537893793408504192074528154430149 + 1/538286441900380211365817285104907086347439746130226973253778132494225813153 + 1/579504587067542801713103191859918608251030291952195423583529357653899418686342360361798689053273749372615043661810228371898539583862011424993909789665


Note also that ${\displaystyle {\tfrac {44}{53}}}$ also has 8 terms.

${\displaystyle {\tfrac {1}{2}}+{\tfrac {1}{4}}+{\tfrac {1}{13}}+{\tfrac {1}{307}}+{\tfrac {1}{120871}}+{\tfrac {1}{20453597227}}+{\tfrac {1}{697249399186783218655}}+{\tfrac {1}{1458470173998990524806872692984177836808420}}}$

## Visual Basic .NET

Translation of: D
Imports System.Numerics
Imports System.Text

Module Module1

Function Gcd(a As BigInteger, b As BigInteger) As BigInteger
If b = 0 Then
If a < 0 Then
Return -a
Else
Return a
End If
Else
Return Gcd(b, a Mod b)
End If
End Function

Function Lcm(a As BigInteger, b As BigInteger) As BigInteger
Return a / Gcd(a, b) * b
End Function

Public Class Rational
Dim num As BigInteger
Dim den As BigInteger

Public Sub New(n As BigInteger, d As BigInteger)
Dim c = Gcd(n, d)
num = n / c
den = d / c
If den < 0 Then
num = -num
den = -den
End If
End Sub

Public Sub New(n As BigInteger)
num = n
den = 1
End Sub

Public Function Numerator() As BigInteger
Return num
End Function

Public Function Denominator() As BigInteger
Return den
End Function

Public Overrides Function ToString() As String
If den = 1 Then
Return num.ToString()
Else
Return String.Format("{0}/{1}", num, den)
End If
End Function

'Arithmetic operators
Public Shared Operator +(lhs As Rational, rhs As Rational) As Rational
Return New Rational(lhs.num * rhs.den + rhs.num * lhs.den, lhs.den * rhs.den)
End Operator

Public Shared Operator -(lhs As Rational, rhs As Rational) As Rational
Return New Rational(lhs.num * rhs.den - rhs.num * lhs.den, lhs.den * rhs.den)
End Operator

'Comparison operators

Public Shared Operator =(lhs As Rational, rhs As Rational) As Boolean
Return lhs.num = rhs.num AndAlso lhs.den = rhs.den
End Operator

Public Shared Operator <>(lhs As Rational, rhs As Rational) As Boolean
Return lhs.num <> rhs.num OrElse lhs.den <> rhs.den
End Operator

Public Shared Operator <(lhs As Rational, rhs As Rational) As Boolean
'a/b < c/d
Dim ad = lhs.num * rhs.den
Dim bc = lhs.den * rhs.num
Return ad < bc
End Operator

Public Shared Operator >(lhs As Rational, rhs As Rational) As Boolean
'a/b > c/d
Dim ad = lhs.num * rhs.den
Dim bc = lhs.den * rhs.num
Return ad > bc
End Operator

Public Shared Operator <=(lhs As Rational, rhs As Rational) As Boolean
Return lhs < rhs OrElse lhs = rhs
End Operator

Public Shared Operator >=(lhs As Rational, rhs As Rational) As Boolean
Return lhs > rhs OrElse lhs = rhs
End Operator

'Conversion operators
Public Shared Widening Operator CType(ByVal bi As BigInteger) As Rational
Return New Rational(bi)
End Operator
Public Shared Widening Operator CType(ByVal lo As Long) As Rational
Return New Rational(lo)
End Operator
End Class

Function Egyptian(r As Rational) As List(Of Rational)
Dim result As New List(Of Rational)

If r >= 1 Then
If r.Denominator() = 1 Then
Return result
End If
result.Add(New Rational(r.Numerator / r.Denominator))
r -= result(0)
End If

Dim modFunc = Function(m As BigInteger, n As BigInteger)
Return ((m Mod n) + n) Mod n
End Function

While r.Numerator() <> 1
Dim q = (r.Denominator() + r.Numerator() - 1) / r.Numerator()
r = New Rational(modFunc(-r.Denominator(), r.Numerator()), r.Denominator * q)
End While

Return result
End Function

Function FormatList(Of T)(col As List(Of T)) As String
Dim iter = col.GetEnumerator()
Dim sb As New StringBuilder

sb.Append("[")
If iter.MoveNext() Then
sb.Append(iter.Current)
End If
While iter.MoveNext()
sb.Append(", ")
sb.Append(iter.Current)
End While
sb.Append("]")
Return sb.ToString()
End Function

Sub Main()
Dim rs = {New Rational(43, 48), New Rational(5, 121), New Rational(2014, 59)}
For Each r In rs
Console.WriteLine("{0} => {1}", r, FormatList(Egyptian(r)))
Next

Dim lenMax As Tuple(Of ULong, Rational) = Tuple.Create(0UL, New Rational(0))
Dim denomMax As Tuple(Of BigInteger, Rational) = Tuple.Create(New BigInteger(0), New Rational(0))

Dim query = (From i In Enumerable.Range(1, 100)
From j In Enumerable.Range(1, 100)
Select New Rational(i, j)).Distinct().ToList()
For Each r In query
Dim e = Egyptian(r)
Dim eLen As ULong = e.Count
Dim eDenom = e.Last().Denominator()
If eLen > lenMax.Item1 Then
lenMax = Tuple.Create(eLen, r)
End If
If eDenom > denomMax.Item1 Then
denomMax = Tuple.Create(eDenom, r)
End If
Next

Console.WriteLine("Term max is {0} with {1} terms", lenMax.Item2, lenMax.Item1)
Dim dStr = denomMax.Item1.ToString()
Console.WriteLine("Denominator max is {0} with {1} digits {2}...{3}", denomMax.Item2, dStr.Length, dStr.Substring(0, 5), dStr.Substring(dStr.Length - 5, 5))
End Sub

End Module

Output:
43/48 => [1/2, 1/3, 1/16]
5/121 => [1/25, 1/757, 1/763309, 1/873960180913, 1/1527612795642093418846225]
2014/59 => [34, 1/8, 1/95, 1/14947, 1/670223480]
Term max is 97/53 with 9 terms
Denominator max is 8/97 with 150 digits 57950...89665

## Wren

Translation of: Kotlin
Library: Wren-big

We use the BigRat class in the above module to represent arbitrary size fractions.

import "./big" for BigInt, BigRat

var toEgyptianHelper // recursive
toEgyptianHelper = Fn.new { |n, d, fracs|
if (n == BigInt.zero) return
var divRem = d.divMod(n)
var div = divRem[0]
if (divRem[1] > BigInt.zero) div = div.inc
var n2 = (-d) % n
if (n2 < BigInt.zero) n2 = n2 + n
var d2 = d * div
var f = BigRat.new(n2, d2)
if (f.num == BigInt.one) {
return
}
toEgyptianHelper.call(f.num, f.den, fracs)
}

var toEgyptian = Fn.new { |r|
if (r.num == BigInt.zero) return [r]
var fracs = []
if (r.num.abs >= r.den.abs) {
var div = BigRat.new(r.num/r.den, BigInt.one)
var rem = r - div
toEgyptianHelper.call(rem.num, rem.den, fracs)
} else {
toEgyptianHelper.call(r.num, r.den, fracs)
}
return fracs
}

BigRat.showAsInt = true
var fracs = [BigRat.new(43, 48), BigRat.new(5, 121), BigRat.new(2014, 59)]
for (frac in fracs) {
var list = toEgyptian.call(frac)
System.print("%(frac) -> %(list.join(" + "))")
}

for (r in [98, 998]) {
if (r == 98) {
System.print("\nFor proper fractions with 1 or 2 digits:")
} else {
System.print("\nFor proper fractions with 1, 2 or 3 digits:")
}
var maxSize = 0
var maxSizeFracs = []
var maxDen = BigInt.zero
var maxDenFracs = []
var sieve = List.filled(r + 1, null) // to eliminate duplicates
for (i in 0..r) sieve[i] = List.filled(r + 2, false)
for (i in 1..r) {
for (j in (i + 1)..(r + 1)) {
if (!sieve[i][j]) {
var f = BigRat.new(i, j)
var list = toEgyptian.call(f)
var listSize = list.count
if (listSize > maxSize) {
maxSize = listSize
maxSizeFracs.clear()
} else if (listSize == maxSize) {
}
var listDen = list[-1].den
if (listDen > maxDen) {
maxDen = listDen
maxDenFracs.clear()
} else if (listDen == maxDen) {
}
if (i < r / 2) {
var k = 2
while (true) {
if (j * k > r + 1) break
sieve[i * k][j * k] = true
k = k + 1
}
}
}
}
}
System.print("  largest number of items = %(maxSize)")
System.print("  fraction(s) with this number : %(maxSizeFracs)")
var md = maxDen.toString
System.write("  largest denominator = %(md.count) digits, ")
System.print("%(md[0...20])...%(md[-20..-1])")
System.print("  fraction(s) with this denominator : %(maxDenFracs)")
}

Output:
43/48 -> 1/2 + 1/3 + 1/16
5/121 -> 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1527612795642093418846225
2014/59 -> 34 + 1/8 + 1/95 + 1/14947 + 1/670223480

For proper fractions with 1 or 2 digits:
largest number of items = 8
fraction(s) with this number : [8/97, 44/53]
largest denominator = 150 digits, 57950458706754280171...62011424993909789665
fraction(s) with this denominator : [8/97]

For proper fractions with 1, 2 or 3 digits:
largest number of items = 13
fraction(s) with this number : [529/914, 641/796]
largest denominator = 2847 digits, 83901882683345018663...38431266995525592705
fraction(s) with this denominator : [36/457, 529/914]


## zkl

Translation of: Tcl
# Just compute the denominator terms, as the numerators are always 1
fcn egyptian(num,denom){
result,t := List(),Void;
t,num=num.divr(denom);      // reduce fraction
if(t) result.append(T(t));  // signal t isn't a denominator
while(num){
# Compute ceil($denom/$num) without floating point inaccuracy
term:=denom/num + (denom/num*num < denom);
result.append(term);
z:=denom%num;
num=(if(z) num-z else 0);
denom*=term;
}
result
}
fcn efrac(fraction){  // list to string, format list of denominators
fraction.pump(List,fcn(denom){
if(denom.isType(List)) denom[0]
else 		     String("1/",denom);
}).concat(" + ")
}
foreach n,d in (T(T(43,48), T(5,121), T(2014,59))){
println("%s/%s --> %s".fmt(n,d, egyptian(n,d):efrac(_)));
}
Output:
43/48 --> 1/2 + 1/3 + 1/16
5/121 --> 1/25 + 1/757 + 1/763309 + 1/873960180913 + 1/1025410058030422033
2014/59 --> 34 + 1/8 + 1/95 + 1/14947 + 1/670223480


For the big denominators, use GMP (Gnu Multi Precision).

var [const] BN=Import("zklBigNum");  // libGMP
lenMax,denomMax := List(0,Void),List(0,Void);
foreach n,d in (Walker.cproduct([1..99],[1..99])){ // 9801 fractions
e,eLen,eDenom := egyptian(BN(n),BN(d)), e.len(), e[-1];
if(eDenom.isType(List)) eDenom=1;
if(eLen  >lenMax[0])   lenMax.clear(eLen,T(n,d));
if(eDenom>denomMax[0]) denomMax.clear(eDenom,T(n,d));
}
println("Term max is %s/%s with %d terms".fmt(lenMax[1].xplode(), lenMax[0]));
dStr:=denomMax[0].toString();
println("Denominator max is %s/%s with %d digits %s...%s"
.fmt(denomMax[1].xplode(), dStr.len(), dStr[0,5], dStr[-5,*]));
Output:
Term max is 97/53 with 9 terms
Denominator max is 8/97 with 150 digits 57950...89665