1 files changed, 50 insertions, 0 deletions
diff --git a/challenge-055/lubos-kolouch/perl/ch-2.pl b/challenge-055/lubos-kolouch/perl/ch-2.pl
new file mode 100644
index 0000000000..d49b674046
--- /dev/null
+++ b/challenge-055/lubos-kolouch/perl/ch-2.pl
@@ -0,0 +1,50 @@
+##!/usr/bin/env perl
+
+use strict;
+use warnings;
+use Math::Combinatorics;
+use Data::Dumper;
+use feature qw/say/;
+
+sub process_all_waves {
+
+    my $arr_ref = shift;
+
+    my @result;
+
+    my $combinat = Math::Combinatorics->new(
+        count => scalar(@$arr_ref),
+        data  => [@$arr_ref],
+    );
+
+    while ( my @permu = $combinat->next_permutation ) {
+        push @result, \@permu if check_wave( \@permu );
+    }
+
+    return \@result;
+}
+
+sub check_wave {
+    my $perm_ref = shift;
+
+    # 1 = greater, -1 = smaller
+    my $direction = 1;
+
+    for ( 0 .. scalar(@$perm_ref) - 2 ) {
+        if ( $direction == 1 ) {
+            # stop if wave is broken
+            return 0 if $$perm_ref[$_] < $$perm_ref[ $_ + 1 ];
+        }
+        else {
+            return 0 if $$perm_ref[$_] > $$perm_ref[ $_ + 1 ];
+        }
+
+        $direction *= -1;
+    }
+
+    return 1;
+}
+
+my $all_waves = process_all_waves( [ 1, 2, 3, 4 ] );
+
+warn Dumper \$all_waves;