LeetCode - 706 设计哈希映射（设计） *

超大数组

class MyHashMap {
    
    private int[] map ;
    public MyHashMap() {
    
       map = new int[1000001];
       Arrays.fill(map,-1);
    }
    
    public void put(int key, int value) {
    
         map[key] = value;
    }
    
    public int get(int key) {
    
        return map[key];
    }
    
    public void remove(int key) {
    
         map[key] = -1;
    }
}

拉链法

class MyHashMap {
    
    class Pair{
    
        private int key;
        private int value;
        public Pair(int key,int value){
    
            this.key = key;
            this.value = value;
        }

        public void setValue(int value){
    
           this.value = value;
        }
        public int getKey(){
    
            return this.key;
        }
        public int getValue(){
    
            return this.value;
        }
    }
    private List<Pair> list[];
    private int capacity;
    public MyHashMap() {
    
          capacity = 1000;
          list = new ArrayList[capacity];
    }
    public int hash(int key){
    
        return key % this.capacity;
    }
    public void put(int key, int value) {
    
         int h = hash(key);
         boolean flag = false;
         if(list[h] != null){
    
             for(int i = 0; i < list[h].size();i++){
    
                 if(list[h].get(i).getKey() == key){
    
                     list[h].get(i).setValue(value);
                     flag = true;
                 }  
             }
             if(flag == false)
               list[h].add(new Pair(key,value));
         }
         else{
    
             list[h] = new ArrayList();
             list[h].add(new Pair(key,value));
         }
    }
    
    public int get(int key) {
    
         int h = hash(key);
         if(list[h] != null){
    
             for(int i = 0; i < list[h].size();i++){
    
                 if(list[h].get(i).getKey() == key)
                     return list[h].get(i).getValue();
             }
         }
         return -1;
    }
    
    public void remove(int key) {
    
         int h = hash(key);
         Pair pair = null;
         if(list[h] != null){
    
             for(int i = 0; i < list[h].size();i++){
    
                 if(list[h].get(i).getKey() == key){
    
                     pair = list[h].get(i);
                     break;
                 }
             }
         }
         if(pair != null)
            list[h].remove(pair);
    }
}

/** * Your MyHashMap object will be instantiated and called as such: * MyHashMap obj = new MyHashMap(); * obj.put(key,value); * int param_2 = obj.get(key); * obj.remove(key); */