380. Insert Delete GetRandom O(1)

https://leetcode.com/problems/insert-delete-getrandom-o1

Python

import random


class RandomizedSet:

    def __init__(self):
        self.memory = set()

    def insert(self, val: int) -> bool:
        if val in self.memory:
            return False
        self.memory.add(val)
        return True

    def remove(self, val: int) -> bool:
        if val in self.memory:
            self.memory.remove(val)
            return True
        return False

    def getRandom(self) -> int:
        picked = random.randrange(0, len(self.memory))
        return list(self.memory)[picked]