So, I wrote a code, for this problem.

Code :

import copy

class SnapshotArray:

    def __init__(self, length: int):
        self.lst = [0] * length
        self.snap_id = -1
        self.hash = []
        self.by_snap_id = 0
        return None

    def set(self, index: int, val: int) -> None:
        self.lst[index] = val
        return None

    def snap(self) -> int:
        self.snap_id += 1
        self.copy = copy.copy(self.lst)
        self.hash.append(self.copy)
        del self.lst
        self.lst = self.hash[self.snap_id]
        return self.snap_id

    def get(self, index: int, snap_id: int) -> int:
        return self.hash[snap_id][index]

In 69 / 75 testcase it says MLE

So I tried to make just one list from which I’ll be taking value for current list too, but it didn’t work. So, how do I reduce amount of memory used?