Implement the `RandomizedSet`

class:

`RandomizedSet()`

Initializes the`RandomizedSet`

object.`bool insert(int val)`

Inserts an item`val`

into the set if not present. Returns`true`

if the item was not present,`false`

otherwise.`bool remove(int val)`

Removes an item`val`

from the set if present. Returns`true`

if the item was present,`false`

otherwise.`int getRandom()`

Returns a random element from the current set of elements (it's guaranteed that at least one element exists when this method is called). Each element must have the**same probability**of being returned.

You must implement the functions of the class such that each function works in **average** `O(1)`

time complexity.

**Example 1:**

Input["RandomizedSet", "insert", "remove", "insert", "getRandom", "remove", "insert", "getRandom"] [[], [1], [2], [2], [], [1], [2], []]Output[null, true, false, true, 2, true, false, 2]ExplanationRandomizedSet randomizedSet = new RandomizedSet(); randomizedSet.insert(1); // Inserts 1 to the set. Returns true as 1 was inserted successfully. randomizedSet.remove(2); // Returns false as 2 does not exist in the set. randomizedSet.insert(2); // Inserts 2 to the set, returns true. Set now contains [1,2]. randomizedSet.getRandom(); // getRandom() should return either 1 or 2 randomly. randomizedSet.remove(1); // Removes 1 from the set, returns true. Set now contains [2]. randomizedSet.insert(2); // 2 was already in the set, so return false. randomizedSet.getRandom(); // Since 2 is the only number in the set, getRandom() will always return 2.

**Constraints:**

`-2`

^{31}<= val <= 2^{31}- 1- At most
`2 *`

`10`

calls will be made to^{5}`insert`

,`remove`

, and`getRandom`

. - There will be
**at least one**element in the data structure when`getRandom`

is called.