98. Design HashMap

Design a HashMap without using any built-in hash table libraries.

Implement the MyHashMap class:

• MyHashMap() initializes the object with an empty map.
• void put(int key, int value) inserts a (key, value) pair into the HashMap. If the key already exists, update the value.
• int get(int key) returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key.
• void remove(int key) removes the key and its corresponding value if the map contains the mapping for the key.

Examples

const map = new MyHashMap();
map.put(1, 1);
map.put(2, 2);
map.get(1);    // 1
map.get(3);    // -1
map.put(2, 1); // update
map.get(2);    // 1
map.remove(2);
map.get(2);    // -1