(LeetCode 面试经典 150 题) 104. 二叉树的最大深度 (深度优先搜索dfs)

思路：深度优先搜索dfs，时间复杂度0(n)。

C++版本：

/*** Definition for a binary tree node.* struct TreeNode {*     int val;*     TreeNode *left;*     TreeNode *right;*     TreeNode() : val(0), left(nullptr), right(nullptr) {}*     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}*     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}* };*/
class Solution {
public:int maxDepth(TreeNode* root) {if(root==nullptr) return 0;int left=maxDepth(root->left);int right=maxDepth(root->right);return max(left,right)+1;}
};## 标题

JAVA版本：

/*** Definition for a binary tree node.* public class TreeNode {*     int val;*     TreeNode left;*     TreeNode right;*     TreeNode() {}*     TreeNode(int val) { this.val = val; }*     TreeNode(int val, TreeNode left, TreeNode right) {*         this.val = val;*         this.left = left;*         this.right = right;*     }* }*/
class Solution {public int maxDepth(TreeNode root) {if(root==null) return 0;int left=maxDepth(root.left);int right=maxDepth(root.right);return Math.max(left,right)+1;}
}

GO版本：

/*** Definition for a binary tree node.* type TreeNode struct {*     Val int*     Left *TreeNode*     Right *TreeNode* }*/
func maxDepth(root *TreeNode) int {if root==nil {return 0}left:=maxDepth(root.Left)right:=maxDepth(root.Right)return max(left,right)+1
}