LeetCode - 705 设计哈希集合（设计）

数组

class MyHashSet {
    
    private boolean[] set;
    public MyHashSet() {
    
        set = new boolean[1000001];
    }
    
    public void add(int key) {
    
        set[key] = true;
    }
    
    public void remove(int key) {
    
        set[key] = false;
    }
    
    public boolean contains(int key) {
    
         return set[key];
    }
}

/** * Your MyHashSet object will be instantiated and called as such: * MyHashSet obj = new MyHashSet(); * obj.add(key); * obj.remove(key); * boolean param_3 = obj.contains(key); */

拉链法

class MyHashSet {
    
    private List<Integer> list[];
    private int capacity;
    public MyHashSet() {
    
        capacity = 1000;
        list = new ArrayList[this.capacity]; 
    }
    public int hash(int key){
    
        return key % this.capacity;
    }
    public void add(int key) {
    
        int h = hash(key);
        if(list[h] == null){
    
            list[h] = new ArrayList<>();
            list[h].add(key);
        }
        else{
    
            if(!list[h].contains((Integer) key))
                list[h].add(key);
        }
    }
    
    public void remove(int key) {
    
        int h = hash(key);
        if(list[h] != null){
    
            if(list[h].contains((Integer) key))
                list[h].remove((Integer) key);
        }
    }
    
    public boolean contains(int key) {
    
       int h = hash(key);
        if(list[h] != null){
    
            if(list[h].contains((Integer) key))
                return true;
            else
                return false;
        }
        else
             return false;
    }
}

/** * Your MyHashSet object will be instantiated and called as such: * MyHashSet obj = new MyHashSet(); * obj.add(key); * obj.remove(key); * boolean param_3 = obj.contains(key); */