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;
    }
}

##</code><code>##

Runtime: 48 ms, faster than 99.40% of Python3 online submissions for Two Sum.
Memory Usage: 15.4 MB, less than 42.44% of Python3 online submissions for Two Sum.

##</code><code>##

class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        seen = dict();
        for i in range(0, len(nums)):
            x = nums[i]
            if target - x in seen:
                return [i, seen[target - x]]
            seen[x] = i