first few days

4/1.pl

@@ -0,0 +1,47 @@
+#!/usr/bin/perl
+
+use strict;
+use v5.10;
+use Data::Dumper;
+
+chomp (my @data = <STDIN>);
+@data = sort @data;
+
+my %sleeps;
+my %most;
+my $currentguard = -1;
+my $sleeptime = -1;
+
+foreach my $line (@data) {
+    say $line;
+    if ( my ($date, $hour, $min, $guard) = 
+        ($line =~ 
+        m/\[(\d{4}-\d{2}-\d{2}) (\d{2}):(\d{2})\] Guard #(\d+) begins shift/) ) {
+            $currentguard = $guard;
+        }
+    elsif ( my ($date, $hour, $min) = 
+        ($line =~ 
+        m/\[(\d{4}-\d{2}-\d{2}) (\d{2}):(\d{2})\] falls asleep/) ) {
+            $sleeptime = $min;
+        }
+    elsif ( my ($date, $hour, $min) = 
+        ($line =~ 
+        m/\[(\d{4}-\d{2}-\d{2}) (\d{2}):(\d{2})\] wakes up/) ) {
+            foreach my $mt ($sleeptime .. $min-1) {
+                $sleeps{$currentguard}->{$mt}++;
+                $most{$currentguard}++;
+            }
+        }
+    else {
+        say "no match"
+    }
+}
+
+my @most = sort { $most{$b} <=> $most{$a} } keys %most; 
+say $most[0] . " most, with " . $most{$most[0]};
+
+my $result = $sleeps{$most[0]};
+my @best = sort { $$result{$b} <=> $$result{$a} } keys %$result; 
+
+say $best[0] . " best minute";
+say ($best[0] * $most[0]);