class RandomizedSet(object):
def __init__(self):
"""
Initialize your data structure here.
"""
self.nums, self.pos = [], {}
def insert(self, val):
"""
Inserts a value to the set. Returns true if the set did not already contain the specified element.
:type val: int
:rtype: bool
"""
if val not in self.pos:
self.nums.append(val)
self.pos[val] = len(self.nums) - 1
return True
return False
def remove(self, val):
"""
Removes a value from the set. Returns true if the set contained the specified element.
:type val: int
:rtype: bool
"""
if val in self.pos:
idx, last = self.pos[val], self.nums[-1]
self.nums[idx], self.pos[last] = last, idx
self.nums.pop(); self.pos.pop(val, 0)
return True
return False
def getRandom(self):
"""
Get a random element from the set.
:rtype: int
"""
return self.nums[random.randint(0, len(self.nums) - 1)]
# Your RandomizedSet object will be instantiated and called as such:
# obj = RandomizedSet()
# param_1 = obj.insert(val)
# param_2 = obj.remove(val)
# param_3 = obj.getRandom()
https://leetcode.com/problems/insert-delete-getrandom-o1/#/solutions
