[104. 二叉树的最大深度](https://leetcode.cn/problems/maximum-depth-of-binary-tree/)

var maxDepth = function(root) {
    if(root===null)return 0
    let leftMax=1
    let rightMax=1
    if(root.left)leftMax=maxDepth(root.left)+1
    if(root.right)rightMax=maxDepth(root.right)+1
    return Math.max(leftMax,rightMax)
};

 

var maxDepth = function(root) {
    if(!root) return 0
    let result=0
    function dfs(node,deep){
        result=Math.max(result,deep)
        if(node.left)dfs(node.left,deep+1)
        if(node.right)dfs(node.right,deep+1)
    }
    dfs(root,1)
    return result
};