Sorting algorithms/Bead sort: Difference between revisions

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Algorithm has O(S), where S is the sum of the integers in the input set: Each bead is moved individually. This is the case when bead sort is implemented without a mechanism to assist in finding empty spaces below the beads, such as in software implementations.
Algorithm has O(S), where S is the sum of the integers in the input set: Each bead is moved individually. This is the case when bead sort is implemented without a mechanism to assist in finding empty spaces below the beads, such as in software implementations.

=={{header|C}}==
A rather straightforward implementation; since we do not use dynamic matrix, we have to know the maximum value in the array in advance. Using no sparse matrix means the matrix needs MAX*MAX times the size of an integer bytes to be stored.

<lang c>#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>

int *bead_sort(int *a, size_t len)
{
size_t i, j, k;
bool fallen;
int *t, *r = NULL;
int max = a[0];

for(i = 1; i < len; i++)
{
if ( a[i] < 0 ) return NULL; // we can't sort nums < 0
if ( max < a[i] ) max = a[i];
}
t = malloc(max*max*sizeof(int));
if ( t == NULL ) return NULL;
memset(t, 0, max*max*sizeof(int));

r = malloc(len*sizeof(int));
memset(r, 0, len*sizeof(int));
if (r != NULL)
{
// "split" numbers into "beads" (units)
for(i = 0; i < len; i++)
{
for(j = 0; j < a[i]; j++) t[i*max + j]++;
}

// make them fall down
do
{
fallen = false;
for(i = 0; i < max-1; i++)
{
for(j = 0; j < max; j++)
{
if ( t[i*max + j] == 1 && t[(i+1)*max + j] == 0 )
{
fallen = true;
t[i*max + j] = 0;
t[(i+1)*max + j] = 1;
}
}
}
} while(fallen);

#if defined(SHOW_BEADS)
for(i = 0; i < max; i++)
{
for(j = 0; j < max; j++)
{
printf("%d ", t[i*max + j]);
}
printf("\n");
}
#endif

// count beads
k = 0;
for(i = 0; i < max; i++)
{
if ( t[(max - i - 1)*max + 0] == 0 ) break;
for(j = 0; j < max; j++)
{
int v = t[(max - i - 1)*max + j];
if ( v == 0 ) break;
r[k] += v;
}
k++;
}
}
free(t);
return r;
}

int main()
{
int values[] = {5, 3, 1, 7, 4, 1, 1, 20};
size_t i, len = sizeof(values)/sizeof(int);

int *r = bead_sort(values, len);
if ( r == NULL ) return EXIT_FAILURE;

for(i = 0; i < len; i++)
{
printf("%d ", r[i]);
}
putchar('\n');

free(r);
return EXIT_SUCCESS;
}</lang>


=={{header|C++}}==
=={{header|C++}}==

Revision as of 13:14, 28 August 2010

Task
Sorting algorithms/Bead sort
You are encouraged to solve this task according to the task description, using any language you may know.

In this task, the goal is to sort an array of positive integers using the Bead Sort Algorithm.

Algorithm has O(S), where S is the sum of the integers in the input set: Each bead is moved individually. This is the case when bead sort is implemented without a mechanism to assist in finding empty spaces below the beads, such as in software implementations.

C

A rather straightforward implementation; since we do not use dynamic matrix, we have to know the maximum value in the array in advance. Using no sparse matrix means the matrix needs MAX*MAX times the size of an integer bytes to be stored.

<lang c>#include <stdio.h>

  1. include <stdlib.h>
  2. include <stdbool.h>
  3. include <string.h>

int *bead_sort(int *a, size_t len) {

 size_t i, j, k;
 bool fallen;
 int *t, *r = NULL;
 int max = a[0];
 for(i = 1; i < len; i++) 
 {
   if ( a[i] < 0 ) return NULL;  // we can't sort nums < 0
   if ( max < a[i] ) max = a[i];
 }
 
 t = malloc(max*max*sizeof(int));
 if ( t == NULL ) return NULL;
 memset(t, 0, max*max*sizeof(int));
 r = malloc(len*sizeof(int));
 memset(r, 0, len*sizeof(int));
 if (r != NULL) 
 {
   // "split" numbers into "beads" (units)
   for(i = 0; i < len; i++)
   {
     for(j = 0; j < a[i]; j++) t[i*max + j]++;
   }
   // make them fall down
   do
   {
     fallen = false;
     for(i = 0; i < max-1; i++)
     {

for(j = 0; j < max; j++) { if ( t[i*max + j] == 1 && t[(i+1)*max + j] == 0 ) { fallen = true; t[i*max + j] = 0; t[(i+1)*max + j] = 1; } }

     }
   } while(fallen);
  1. if defined(SHOW_BEADS)
   for(i = 0; i < max; i++)
   {
     for(j = 0; j < max; j++)
     {

printf("%d ", t[i*max + j]);

     }
     printf("\n");
   }
  1. endif
   // count beads
   k = 0;
   for(i = 0; i < max; i++)
   {
     if ( t[(max - i - 1)*max + 0] == 0 ) break;
     for(j = 0; j < max; j++)
     {

int v = t[(max - i - 1)*max + j]; if ( v == 0 ) break; r[k] += v;

     }
     k++;
   }
   
 }
 free(t);
 return r;

}

int main() {

 int values[] = {5, 3, 1, 7, 4, 1, 1, 20};
 size_t i, len = sizeof(values)/sizeof(int);
 int *r = bead_sort(values, len);
 if ( r == NULL ) return EXIT_FAILURE;
 for(i = 0; i < len; i++)
 {
   printf("%d ", r[i]);
 }
 putchar('\n');
 free(r);
 return EXIT_SUCCESS;

}</lang>

C++

<lang cpp>//this algorithm only works with positive, whole numbers. //O(2n) time complexity where n is the summation of the whole list to be sorted. //O(3n) space complexity.

  1. include<iostream>
  2. include<vector>

using namespace std;

void distribute( int dist, vector<int> &List)//*beads* go down into different buckets using gravity (addition). {

   if (dist > List.size() )
       List.resize(dist,0); //resize if too big for current vector
   for (int i=0; i < dist; i++)
       List[i] = List[i]+1;

}

int main() {

   vector<int> list;
   vector<int> list2;
   int myints[] = {5,3,1,7,4,1,1};
   vector<int> fifth (myints, myints + sizeof(myints) / sizeof(int) );
   cout << "#1 Beads falling down: ";
   for (int i=0; i < fifth.size(); i++)
       distribute (fifth[i], list);
   cout << endl;
   cout <<endl<< "Beads on their sides: ";
   for (int i=0; i < list.size(); i++)
       cout << " " << list[i];
   cout << endl;	
   //second part
   cout << "#2 Beads right side up: ";
   for (int i=0; i < list.size(); i++)
       distribute (list[i], list2);
   cout << endl;
   cout <<endl<< "Sorted list/array";
   for (int i=0; i < list2.size(); i++)
       cout << " " << list2[i];
   cout << endl;
   return 0;

}</lang>

Output:

Beads falling down:

Beads on their sides: 7 4 4 3 2 1 1 Beads right side up:

Sorted list/array 7 5 4 3 1 1 1

Haskell

<lang haskell>import Data.List

beadSort :: [Int] -> [Int] beadSort = map sum. transpose. transpose. map (flip replicate 1)</lang> Example; <lang haskell>*Main> beadSort [2,4,1,3,3] [4,3,3,2,1]</lang>

J

<lang j>bead=: [: +/ #"0&1</lang>

Example use:

<lang> bead bead 2 4 1 3 3 4 3 3 2 1

  bead bead 5 3 1 7 4 1 1

7 5 4 3 1 1 1</lang>

Tcl

<lang tcl>package require Tcl 8.5

proc beadsort numList {

   # Special case: empty list is empty when sorted.
   if {![llength $numList]} return
   # Set up the abacus...
   foreach n $numList {

for {set i 0} {$i<$n} {incr i} { dict incr vals $i }

   }
   # Make the beads fall...
   foreach n [dict values $vals] {

for {set i 0} {$i<$n} {incr i} { dict incr result $i }

   }
   # And the result is...
   dict values $result

}

  1. Demonstration code

puts [beadsort {5 3 1 7 4 1 1}]</lang> Output:

7 5 4 3 1 1 1