Day 20: alternative solution wit list of pairs - slower but prettier

[aoc.git] / 2022 / 40.pl

diff --git a/2022/40.pl b/2022/40.pl
index b6e9ff429e77485cdecc5346f277930fbbec0697..5451455a5ea0d9105c5e7b3697f79ed6ba48177d 100755 (executable)
--- a/2022/40.pl
+++ b/2022/40.pl
@@ -4,30 +4,26 @@ use v5.36;
 use strict;
 
 my $key = 811589153;
-my @list = map { $key * $_ } <>;
-my @perm = ( 0 .. $#list );
+my $i = 0;
+my @list = map { [$i++, $key * $_] } <>;
 
 for (1 .. 10) {
        for my $idx (0 .. $#list) {
-               my $move = $list[$idx];
-               my $pos = 0;
-               $pos++ while $perm[$pos] != $idx;
-               splice(@perm, $pos, 1);
-               my $dst = ($pos + $move) % @perm;
-               splice(@perm, $dst, 0, $idx);
+               my $i = 0;
+               $i++ while $list[$i][0] != $idx;
+               my $item = splice @list, $i, 1;
+               my $dest = ($item->[1] + $i) % @list;
+               splice @list, $dest, 0, $item;
        }
 }
 
-my @ordered = map { $list[$perm[$_]] } 0 .. $#list;
-
-my $i = 0;
-$i++ while $ordered[$i] != 0;
-
+$i = 0;
+$i++ while $list[$i][1] != 0;
 my $sum;
 for (1 .. 3) {
        $i += 1000;
-       $i %= @ordered;
-       $sum += $ordered[$i];
+       $i %= @list;
+       $sum += $list[$i][1];
 }
 
 say $sum;