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.
Again, it is.
https://github.com/python/cpython/blob/2d080347d74078a55c477...
This is the memmove() I mentioned above. Like, I actually perf-d the code and confirmed this is in the hot loop.
> but 1553D was not part of that.
Someone submitted this 1553D code to Codeforces and it passed: https://codeforces.com/contest/1553/submission/144971343