This returns -1 if the answer is negative. 
sub comp {
    my ($f, $s) = @_;
    return -1 if length ($f) != length ($s);

    local $_ = $f ^ $s;
    return -1 unless tr/\x00/1/c == 2;

    index $_ => "11";
}

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Abigail

In reply to Re: Detecting transpositions by Abigail-II
in thread Detecting transpositions by BrowserUk

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