class RandomizedCollection:

    #TC: O(1) for all operations
    #SC: O(n)

    def __init__(self):
        """
        Initialize your data structure here.
        """

        self.val_idx = collections.defaultdict(set)
        self.idx_val = {}

        self.count = 0

    def insert(self, val: int) -> bool:
        """
        Inserts a value to the collection. Returns true if the collection did not already contain the specified element.
        """
        self.count += 1
        Bool = True
        if val in self.val_idx:
            Bool = False

        self.val_idx[val].add(self.count)
        self.idx_val[self.count] = val

        return Bool        


    def remove(self, val: int) -> bool:
        """
        Removes a value from the collection. Returns true if the collection contained the specified element.
        """

        if val not in self.val_idx:
            return False
        else:

            gap_idx = self.val_idx[val].pop()

            if len(self.val_idx[val]) == 0:
                del self.val_idx[val]

            if gap_idx != self.count:
                move_val = self.idx_val[self.count]
                self.val_idx[move_val].remove(self.count)
                self.val_idx[move_val].add(gap_idx)
                self.idx_val[gap_idx] = move_val
            del self.idx_val[self.count]

            self.count -= 1

            return True        

    def getRandom(self) -> int:
        """
        Get a random element from the collection.
        """

        rand = randint(1, self.count)
        return self.idx_val[rand]

# Your RandomizedCollection object will be instantiated and called as such:
# obj = RandomizedCollection()
# param_1 = obj.insert(val)
# param_2 = obj.remove(val)
# param_3 = obj.getRandom()