7. Design HashMap

class MyHashMap {
    
    private int[] hash;
    /** Initialize your data structure here. */
    public MyHashMap() {
        hash = new int[100001];
    }
    
    /** value will always be non-negative. */
    public void put(int key, int value) {
        hash[key] = value + 1;
    }
    
    /** Returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key */
    public int get(int key) {
        return hash[key] - 1;
    }
    
    /** Removes the mapping of the specified value key if this map contains a mapping for the key */
    public void remove(int key) {
        hash[key] = 0;
    }
}


	class MyHashMap {

		/** Initialize your data structure here. */
		LinkedList<Entry>[] map;
		public static int SIZE = 769;
		public MyHashMap() {
			map = new LinkedList[SIZE];
		}

		/** value will always be non-negative. */
		public void put(int key, int value) {
			int bucket = key % SIZE;
			if(map[bucket] == null) {
				map[bucket] = new LinkedList<Entry>();
				map[bucket].add(new Entry(key, value));
			}
			else {
				for(Entry entry : map[bucket]){
					if(entry.key == key){
						entry.val = value;
						return;
					}
				}
				map[bucket].add(new Entry(key, value));
			}
		}

		/** Returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key */
		public int get(int key) {
			int bucket = key % SIZE;
			LinkedList<Entry> entries = map[bucket];
			if(entries == null) return -1;
			for(Entry entry : entries) {
				if(entry.key == key) return entry.val;
			}
			return -1;
		}

		/** Removes the mapping of the specified value key if this map contains a mapping for the key */
		public void remove(int key) {
			int bucket = key % SIZE;
			Entry toRemove = null;
			if(map[bucket] == null) return;
			else {
				for(Entry entry : map[bucket]){
					if(entry.key == key) {
						toRemove = entry;
					}
				}
				if(toRemove == null) return;
				map[bucket].remove(toRemove);
			}
		}
	}

	class Entry {
		public int key;
		public int val;

		public Entry(int key, int val){
			this.key = key;
			this.val = val;
		}
	}