碎碎念倒霉熊不是停播了吗...虽然今天pre还不错但明天还有一场恶仗啊啊啊加油题目代码详细思路指路【leetcode】104.二叉树的最大深度这里就直接贴代码了。DFS/** * Definition for a binary tree node. * function TreeNode(val, left, right) { * this.val (valundefined ? 0 : val) * this.left (leftundefined ? null : left) * this.right (rightundefined ? null : right) * } */ /** * param {TreeNode} root * return {number} */ var maxDepth function(root) { if (root null) return 0 let l_depth maxDepth(root.left) let r_depth maxDepth(root.right) return Math.max(l_depth, r_depth) 1 };BFS/** * Definition for a binary tree node. * function TreeNode(val, left, right) { * this.val (valundefined ? 0 : val) * this.left (leftundefined ? null : left) * this.right (rightundefined ? null : right) * } */ /** * param {TreeNode} root * return {number} */ var maxDepth function(root) { if (root null) return 0 const q [] q.push(root) let len q.length let depth 0 while (q.length 0) { let len q.length while (len 0) { let node q[0] if (node.left ! null) q.push(node.left) if (node.right ! null) q.push(node.right) q.shift() len-- } depth } return depth };