java codility training Genomic-range-query

Question

The task is:

A non-empty zero-indexed string S is given. String S consists of N characters from the set of upper-case English letters A, C, G, T.

<

Answer 1

perl 100/100 solution:

sub solution {
    my ($S, $P, $Q)=@_; my @P=@$P; my @Q=@$Q;

    my @_A = (0), @_C = (0), @_G = (0), @ret =();
    foreach (split //, $S)
    {
        push @_A, $_A[-1] + ($_ eq 'A' ? 1 : 0);
        push @_C, $_C[-1] + ($_ eq 'C' ? 1 : 0);
        push @_G, $_G[-1] + ($_ eq 'G' ? 1 : 0);
    }

    foreach my $i (0..$#P)
    {
        my $from_index = $P[$i];
        my $to_index = $Q[$i] + 1;
        if ( $_A[$to_index] - $_A[$from_index] > 0 )
        {
            push @ret, 1;
            next;
        }
        if ( $_C[$to_index] - $_C[$from_index] > 0 )
        {
            push @ret, 2;
            next;
        }
        if ( $_G[$to_index] - $_G[$from_index] > 0 )
        {
            push @ret, 3;
            next;
        }
        push @ret, 4
    }

    return @ret;
}