From 312d690d057b0d17560df3b855cb9b50c5aa8381 Mon Sep 17 00:00:00 2001
From: Christian Segundo
Date: Mon, 4 Dec 2023 12:31:10 +0100
Subject: add day 4

---
 04.pl | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100755 04.pl

(limited to '04.pl')

diff --git a/04.pl b/04.pl
new file mode 100755
index 0000000..3a1e629
--- /dev/null
+++ b/04.pl
@@ -0,0 +1,38 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+
+use File::Slurp;
+
+my ( $o, $t ) = ( 0, 0 );
+
+foreach ( read_file('04.txt') ) {
+  $_ =~ s/Card\s+\d+:\s+//;
+  my ( $i, $j ) = split( /\s+\|\s+/, $_ );
+  my %k = map  { $_ => 1 } split( /\s+/, $i );
+  my @v = grep { $k{$_} } split( /\s+/, $j );
+  next unless scalar(@v);
+  $o = scalar(@v) == 1 ? $o + 1 : $o + 2**( scalar(@v) - 1 );
+}
+
+print( $o . "\n" );
+
+my @c = map {
+  chomp;
+  s/Card\s+\d+:\s+//;
+  my ( $z, $j ) = split( /\s+\|\s+/, $_ );
+  my %k = map  { $_ => 1 } split( /\s+/, $z );
+  my @v = grep { $k{$_} } split( /\s+/, $j );
+  { i => scalar(@v), j => 1 }
+} read_file('04.txt');
+
+for ( my $j = 0 ; $j < scalar(@c) ; $j++ ) {
+  for ( 1 .. $c[$j]->{j} ) {
+    for ( $j + 1 .. $j + $c[$j]->{i} ) {
+      $c[$_]->{j}++;
+    }
+  }
+  $t += $c[$j]->{j};
+}
+
+print $t . "\n";
-- 
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