AoC day 15, Perl (faster)

#!/usr/bin/perl

my @list = map { chomp; split /,/ } <>;
my @hash;
$hash[29999999] = undef;

foreach my $t (0 .. $#list - 1) {
    $hash[ $list[$t] ] = $t + 1;
}

my ($next, $curr) = (int($list[-1]), 0);
foreach my $t ($#list + 1 .. 29999999) {
    $curr = $next;
    $next = (defined $hash[$curr]) ? $t - $hash[$curr] : 0;
    $hash[$curr] = $t;
}
print "$next\n";