would you please explain what did you use

my question is how to think for solutions like these

bravo

We essentialy have the same logic but I love how your's is easier to read.

It was to pass the old requirements where you could be passed None, obviously now that the requirements are changed there is no reason to have it there.

y're right,works without, probably reflex or lazyness to improve a working code :)

I'm assuming that if input else input is there to handle empty lists. In that case, it's not actually needed, as a sorted empty list is still an empty list.

everyone seems to ahve used cramers rule. much simpler than gaussian and numerically and complexity wise fine for 2x2 system

Thanks :)

this one's nice

It seem that this issue still appears:

[1, 2, 5, 6, 7, 8, 10, 11, 11, 12, 12, 13, 16, 17, 19, 21, 27, 32, 33, 34, 37, 37, 39, 47, 50, 51, 53, 54, 55, 56, 57, 65, 65, 68, 68, 68, 70, 71, 76, 78, 81, 82, 83, 84, 85, 86, 87, 91, 91, 98]

should equal

[1, 2, 5, 6, 7, 8, 10, 11, 11, 12, 12, 13, 16, 17, 19, 21, 32, 33, 34, 37, 37, 39, 47, 50, 51, 53, 54, 55, 56, 57, 65, 65, 68, 68, 68, 70, 71, 76, 78, 81, 82, 83, 84, 85, 86, 87, 91, 91, 98]

The number 27 belongs to initial list but disappear in authour's test solution for some reason...

Amazing formula

No problem :)

Oh i don't know why i thought it was the polygon method of finding the area (Which you can't do in this problem). Thank you for the clarification.