#!/usr/bin/env python3 # -*- coding: utf-8 -*- # author: bt3gl import random class RandomizedSet: def __init__(self): self.set = [] self.dict = {} def insert(self, val: int) -> bool: if val in self.dict: return False self.set.append(val) self.dict[val] = len(self.set) return True def remove(self, val: int) -> bool: if val in self.dict: last_element, idx = self.set[-1], self.dict[val] self.set[idx], self.dict[last_element] = last_element, idx self.set.pop() del self.dict[val] return True return False def get_random(self) -> int: return random.choice(self.set)