js实现字典树

 

 

 

//字典树和链表的区别，是node.next指向一个node 或 node[]的区别
function Node(){
   this.next=[];
    this.value= null;
}

function TrieST(){
    this.root = new Node();
    
    this.put = (key,value)=>{
       _put(this.root, key ,value,0);
    }
    this.get = (key)=>{
        let res = _get(this.root, key, 0);
        if(res === null || res === undefined){
            return null;}
            return res.value;
    }
    this.contains = (key)=>{
        let res = this.get(key);
        if(res !== null && res !== undefined ){
            return true;
            }
        return false;
    }
    function _put (x,key,val,i) {
        //如果不存在，初始化
        if(x === null || x === undefined){
            x = new Node();
            }
        //如果找到了，无论之前存在与否，更新它储存的值
        if(i== key.length){
            x.value = val;

            return x;
        }
        //当前字符
        let c = key.charAt(i);
        //下一个字符
        //设定在X.next中,key[i]的值
        x.next[c] =_put(x.next[c],key,val,i+1);
        //返回key[i]对应的Node到树中
        return x;
    }
    function _get (x,key,i) {
        if(x=== null || x === undefined){
            return null;
        }
        //如果当前值是要的值，返回
        if(i == key.length){
            return x;
        }
        let c = key.charAt(i);
        return _get(x.next[c],key,i+1);

    }
}

let tries= new TrieST(); 
tries.put("heheh",10);

console.log(tries)

//...