I didn't see a Perl solution in the Triangles Challenge. Everyone there seems to love Lisp.
Can anyone defend Perl's honor?
Re:Done!! :-)
cog on 2005-01-28T19:02:18
#!/usr/bin/perl
use warnings;
use strict;
use Math::Combinatorics;
my %points = (
0 => [ 0.. 10 ],
1 => [ 0.. 10 ],
2 => [ 4, 6, 1, 3, 5, 0 ],
3 => [ 5, 2, 1, 7, 9, 0 ],
4 => [ 6, 2, 0, 7, 8, 1 ],
5 => [ 0, 8, 10, 2, 1 ],
6 => [ 10, 9, 1, 4, 2, 0 ],
7 => [ 8, 9, 3, 4, 1, 0 ],
8 => [ 10, 0, 5, 7, 4, 1 ],
9 => [ 10, 6, 1, 0, 3, 7 ],
10 => [ 0, 5, 8, 1, 6, 9 ],
);
my @lines = (
[ 0, 5, 8, 10 ],
[ 0, 3, 7, 9 ],
[ 0, 2, 4, 6 ],
[ 0, 1 ],
[ 1, 6, 9, 10 ],
[ 1, 4, 7, 8 ],
[ 1, 2, 3, 5 ],
);
print "There are ", (scalar grep {is_triangle(@$_)} combine(3,0..10)), " triangles.\n";
sub is_triangle {
(grep {$_ eq $_[1]} @{$points{$_[0]}}) &&
(grep {$_ eq $_[2]} @{$points{$_[0]}}) &&
(grep {$_ eq $_[2]} @{$points{$_[1]}}) &&
! grep { 3 == grep { $_ eq $_[0] or $_ eq $_[1] or $_ eq $_[2] } @$_ } @lines;
}
Re:Done!! :-)
Mr. Muskrat on 2005-01-29T03:59:56
Good job. It passes the second test shown on the page too.
#!/usr/bin/perl
use warnings;
use strict;
use Math::Combinatorics;
# I removed the points 0, 2, 4, 6 and the line from 0 6
# Resulting in the second example which has 15 triangles
my %points = (
0 => [ 0, 1, 3, 5, 7.. 10 ],
1 => [ 0, 1, 3, 5, 7.. 10 ],
3 => [ 5, 1, 7, 9, 0 ],
5 => [ 0, 8, 10, 1 ],
7 => [ 8, 9, 3, 1, 0 ],
8 => [ 10, 0, 5, 7, 1 ],
9 => [ 10, 1, 0, 3, 7 ],
10 => [ 0, 5, 8, 1, 9 ],
);
my @lines = (
[ 0, 5, 8, 10 ],
[ 0, 3, 7, 9 ],
[ 0, 1 ],
[ 1, 9, 10 ],
[ 1, 7, 8 ],
[ 1, 3, 5 ],
);
print "There are ", (scalar grep {is_triangle(@$_)} combine(3,0..10)), " triangles.\n";
sub is_triangle {
(grep {$_ eq $_[1]} @{$points{$_[0]}}) &&
(grep {$_ eq $_[2]} @{$points{$_[0]}}) &&
(grep {$_ eq $_[2]} @{$points{$_[1]}}) &&
! grep { 3 == grep { $_ eq $_[0] or $_ eq $_[1] or $_ eq $_[2] } @$_ } @lines;
}Re:Done!! :-)
cog on 2005-01-29T14:08:13
There was a second test?:-|
