二叉树的层序遍历

var levelOrder = function (root) {            if (!root) {                return []            }            let queue = [root];            let res = []            while (queue.length > 0) {                let subArr = []                let length = queue.length                for (let i = 0; i < length; i++) {                    let pop = queue.shift();                    subArr.push(pop.val)                    if (pop.left) queue.push(pop.left)                    if (pop.right) queue.push(pop.right)                }                res.push(subArr)            }            return res;        };

2中序遍历

var inorderTraversal = function(root) {    let result=[]    const rescruion=function(root){        if(root==null){            return null        }        rescruion(root.left)        result.push(root.val)        rescruion(root.right)    }    rescruion(root)    return result};