sub two_sum_choroba {
    my ($input, $target) = @_;
    my %seen;
    for my $i (0 .. $#$input) {
        my $x = $input->[$i];

        return [$i, $seen{ $target - $x }]
            if exists $seen{ $target - $x };

        $seen{$x} = $i;
    }
}