Apologies, I thought you meant ‘optimized’ in a different sense, not in terms of how list.pop is implemented, as AlphaCode wasn't involved in that. You are entirely correct that list.pop uses memmove.

> Someone submitted this 1553D code to Codeforces and it passed

Ah, well that shows you have a 2 second time limit, which is quite a lot of time! Not quite enough to empty a 200k element list with list.pop(0)s, but not far off; a 140k element list squeaks in under the time limit for me.