class RandomizedSet {        Map
     
       indexMap;    List
      
        indexes;        /** Initialize your data structure here. */    public RandomizedSet() {        indexes = new ArrayList<>();        indexMap = new HashMap<>();    }        /** Inserts a value to the set. Returns true if the set did not already contain the specified element. */    public boolean insert(int val) {        if (indexMap.containsKey(val)) {            return false;        }        indexMap.put(val, indexes.size());        indexes.add(val);        return true;    }        /** Removes a value from the set. Returns true if the set contained the specified element. */    public boolean remove(int val) {        if (!indexMap.containsKey(val)) {            return false;        }                 int index = indexMap.get(val);        if (index < indexes.size() - 1) {            indexMap.put(indexes.get(indexes.size() - 1), index);            indexes.set(index, indexes.get(indexes.size() - 1));        }        indexMap.remove(val);        indexes.remove(indexes.size() - 1);        return true;    }        /** Get a random element from the set. */    public int getRandom() {        return indexes.get(new Random().nextInt(indexes.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(); */
      
     

Follow up questions, what if dup allows:

1. Map<Value, Queue<Indexes>> if it looks like a queue first in first out.

2. Map<Value, Map<Index, Indexes>> User can remove the nth value.