adventofcode/2024/05/Part2.pm
2024-12-10 18:34:16 -05:00

64 lines
1.3 KiB
Perl

use lib '.';
use Part1;
package Part2;
use 5.36.0;
use experimental 'declared_refs';
no warnings qw/ uninitialized /;
use List::AllUtils qw/ sum /;
sub read_input ($file) {
my ( $ordering, $manuals ) = split "\n\n", $file->slurp;
$ordering = [ map { [ split '\|' ] } split "\n", $ordering ];
$manuals = [ split "\n", $manuals ];
return { ordering => $ordering, manuals => $manuals };
}
use List::AllUtils qw/ first_index all /;
sub reshuffle_manual ( $ordering, $manual ) {
my @m = split ',', $manual;
my @ordering = grep {
my @o = @$_;
my $i = first_index { $_ == $o[0] } @m;
my $j = first_index { $_ == $o[1] } @m;
all { $_ > -1 } $i, $j;
} @$ordering;
my $redo = 1;
while ($redo) {
$redo = 0;
for my \@o(@ordering) {
my $i = first_index { $_ == $o[0] } @m;
my $j = first_index { $_ == $o[1] } @m;
next if $i < $j;
$redo = 1;
@m[ $i, $j ] = @m[ $j, $i ];
}
}
return join ',', @m;
}
sub solve ($input) {
return sum
map {
my @m = split ',';
$m[ @m / 2 ];
}
map { reshuffle_manual( $input->{ordering}, $_ ) }
grep { !Part1::good_manual( $input->{ordering}, $_ ) }
$input->{manuals}->@*;
}
1;