LeetCode 380. Insert Delete GetRandom O(1)

public class RandomizedSet {    Random random;	Set<Integer> set;    /** Initialize your data structure here. */    public RandomizedSet() {        random = new Random();        set = new HashSet<Integer>();    }        /** Inserts a value to the set. Returns true if the set did not already contain the specified element. */    public boolean insert(int val) {        return set.add(val);    }        /** Removes a value from the set. Returns true if the set contained the specified element. */    public boolean remove(int val) {        return set.remove(val);    }        /** Get a random element from the set. */    public int getRandom() {        return (Integer)set.toArray()[random.nextInt(set.size())];    }}/** * Your RandomizedSet object will be instantiated and called as such: * RandomizedSet obj = new RandomizedSet(); * boolean param_1 = obj.insert(val); * boolean param_2 = obj.remove(val); * int param_3 = obj.getRandom(); */