Pythagorean triples: Difference between revisions

=={{header|Perl 6}}==

This is a fairly naive brute force implementation that is not really practical for large perimeter limits. 100 is no problem. 1000 is slow. 10000 is glacial.

Works with Rakudo 11.06.

<lang perl6>my %trips;

my $limit = 100;

for 3 .. $limit/2 -> $c {

for 1 .. $c-1 -> $a {

my $b = ($c ** 2 - $a **2).sqrt;

last if $c + $a + $b > $limit;

if $b == $b.Int {

my $key = ~($a, $b, $c).sort;

next if %trips.exists($key);

%trips{$key} = ([gcd] $c, $a, $b.Int) > 1 ?? 0 !! 1;

}

}

}

say "There are {+%trips.keys} Pythagorean Triples with a perimeter less than $limit,"

~" of which {[+] %trips.values} are primitive.";

for %trips.keys.sort( {$^a.lc.subst(/(\d+)/,->$/{0~$0.chars.chr~$0},:g)} ) -> $k {

say $k.fmt("%14s"), %trips{$k} ?? ' - primitive' !! '';

}</lang>

<pre>There are 17 Pythagorean Triples with a perimeter less than 100, of which 7 are primitive.

3 4 5 - primitive

5 12 13 - primitive

6 8 10

7 24 25 - primitive

8 15 17 - primitive

9 12 15

9 40 41 - primitive

10 24 26

12 16 20

12 35 37 - primitive

15 20 25

15 36 39

16 30 34

18 24 30

20 21 29 - primitive

21 28 35

24 32 40</pre>