#!/usr/bin/perl use strict; use warnings; my @nodes= qw(A B C D E F G H I J); my %edges= ( A => [qw(B C F I D G J E)], B => [qw(A C D E F H J I)], C => [qw(A B D E F I)], D => [qw(A C B E G J)], E => [qw(A D C B G H I J)], F => [qw(B C A H J I)], G => [qw(D A E H I J)], H => [qw(F B G E I J)], I => [qw(B F C A H G E J)], J => [qw(E G D A H F B I)], ); my @lines=( [qw(A C F I)], [qw(A D G J)], [qw(B C D E)], [qw(B F H J)], [qw(E G H I)], ); my $lines= join("\n", map join(" ", sort @$_),@lines); my %triangle; foreach my $a (@nodes) { foreach my $b (@{$edges{$a}}) { foreach my $c (@{$edges{$b}}) { next if $c eq $a; foreach my $d (@{$edges{$c}}) { next if $d eq $b; next unless $d eq $a; my $triangle= join(' ', sort($a, $b, $c)); my $re= join(' (\S+ )*', sort($a, $b, $c)); next if $lines=~ /$re/; ++$triangle{$triangle}; } } } } print join("\n", scalar keys %triangle, sort keys %triangle),"\n";