剑指Offer 37 - 序列化与反序列化二叉树

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */

/**
 * Encodes a tree to a single string.
 *
 * @param {TreeNode} root
 * @return {string}
 */
var serialize = function(root) {
    if(!root)   return "[]";
    
    let res = "";
    const queue = [root];
    while(queue.length){
        const head = queue.shift();
        if(head){
            res += `${head.val},`;
            queue.push(head.left);
            queue.push(head.right);
        }else{
            res += "#,";
        }
    }
    
    //删去最后一个，
    res = res.substring(0, res.length-1);
    
    return `[${res}]`;
};

/**
 * Decodes your encoded data to tree.
 *
 * @param {string} data
 * @return {TreeNode}
 */
var deserialize = function(data) {
    //"[]"
    if(data.length <= 2) {
        return null;
    }
    
    const nodes = data.substring(1, data.length-1).split(‘,‘);
    const root = new TreeNode(parseInt(nodes.shift()));
    const queue = [root];
    
    while(queue.length){
        const cur = queue.shift();
        const leftVal = nodes.shift();
        if(leftVal !== "#"){
            cur.left = new TreeNode(leftVal);
            queue.push(cur.left);
        }
        
        const rightVal = nodes.shift();
        if(rightVal !== "#"){
            cur.right = new TreeNode(rightVal);
            queue.push(cur.right);
        }
    }
    
    return root;
};

/**
 * Your functions will be called as such:
 * deserialize(serialize(root));
 */