part 1

2018/04/sol1.pl

@@ -0,0 +1,49 @@
+use 5.20.0;
+use warnings;
+
+use List::AllUtils qw/ before after_incl indexes sum pairs pairmap first /;
+use List::UtilsBy qw/ partition_by max_by /;
+
+use experimental qw/
+    signatures
+    postderef
+/;
+
+my @entries = sort <>;
+
+say $_ for @entries;
+
+my %sleep;
+
+my $guard;
+my $start;
+for ( @entries ) {
+    if( /#(\d+)/ ) { $guard = $1; }
+    elsif( /0?(\d+)\] falls asleep/ ) { $start = $1; }
+    elsif( /0?(\d+)\] wakes/ ) { 
+        push $sleep{$guard}->@*, [ $start, $1 ];
+    }
+}
+
+use DDP;
+my %nappers = pairmap { $a => sum map { $_->[1] - $_->[0] } @$b } %sleep;
+p %nappers;
+my( $worst ) = map { $_->[0] } max_by { $_->[1] } pairs %nappers;
+
+#p $sleep{$worst};
+
+say "worst offender: $worst";
+my @x = pairs pairmap { $a => sum map { $_->[1] - $_->[0] } @$b } %sleep;
+
+# p @x;
+
+my %times = pairmap { $a => scalar @$b } partition_by { $_ }  map { $_->[0]..$_->[1]-1 } $sleep{$worst}->@*;
+p %times;
+my ($minute) = map { $_->[0] } max_by { $_->[1] } pairs  %times;
+
+say $minute;
+
+say "$worst, $minute ", $guard * $minute;
+
+say $worst * $minute;
+# 51618 is too low

2018/04/test

@@ -0,0 +1,17 @@
+[1518-11-01 00:00] Guard #10 begins shift
+[1518-11-01 00:05] falls asleep
+[1518-11-01 00:25] wakes up
+[1518-11-01 00:30] falls asleep
+[1518-11-01 00:55] wakes up
+[1518-11-01 23:58] Guard #99 begins shift
+[1518-11-02 00:40] falls asleep
+[1518-11-02 00:50] wakes up
+[1518-11-03 00:05] Guard #10 begins shift
+[1518-11-03 00:24] falls asleep
+[1518-11-03 00:29] wakes up
+[1518-11-04 00:02] Guard #99 begins shift
+[1518-11-04 00:36] falls asleep
+[1518-11-04 00:46] wakes up
+[1518-11-05 00:03] Guard #99 begins shift
+[1518-11-05 00:45] falls asleep
+[1518-11-05 00:55] wakes up