Nice stackless solution !, it is very clear (at least to me.) More

Nice and clear ! When you look at it, your code is actually pretty fast. When you look at the performance, you will notice that most of the time is spent in creating the "m" value. Line # Hits Time Per Hit % Time Line Contents 7 More

This is a clear code ! There is only the minimum comments you actually need... The only change I might suggest is to do the clearing of the identical pairs (if pair[0] != pair[1]) when you create the pairs tuple. By being simple, it is also fast, I find it actually faster (in most cases of cou More