1 files changed, 35 insertions, 0 deletions
diff --git a/challenge-233/kjetillll/perl/ch-2.pl b/challenge-233/kjetillll/perl/ch-2.pl
new file mode 100644
index 0000000000..1a7d6d7c58
--- /dev/null
+++ b/challenge-233/kjetillll/perl/ch-2.pl
@@ -0,0 +1,35 @@
+
+@ARGV ? print join(',', frequency_sort( @ARGV ))."\n"
+      : run_tests();
+
+sub frequency_sort {
+    my %freq;
+    $freq{$_}++ for @_;              #count the input ints
+    sort {                           #return sort of @_ by:
+	$freq{$a} <=> $freq{$b}      #increasing frequency
+	or                           #or
+	$b <=> $a                    #decreasing int
+    }
+    @_;
+}
+
+sub run_tests {
+    for(
+	{
+	    Input  => [1,1,2,2,2,3],
+	    Output => [3,1,1,2,2,2]
+	},
+	{
+	    Input  => [2,3,1,3,2],
+	    Output => [1,3,3,2,2]
+	},
+	{
+	    Input  => [-1,1,-6,4,5,-6,1,4,1],
+	    Output => [5,-1,4,4,-6,-6,1,1,1]
+	}
+    ){
+	my($input,$expected)=@$_{qw(Input Output)};
+	my @got = frequency_sort( @$input );
+	print "@got" eq "@$expected" ? 'ok' : '***ERROR', "\n";
+    }
+}