104. Maximum Depth of Binary Tree LeetCode

Given a binary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

思路：递归



java语言

/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public int maxDepth(TreeNode root) {
if (root == null) {
return 0;
}
if (root.left == null && root.right == null) {
return 1;
}
int leftDepth = 0;
int rightDepth = 0;
if (root.left != null) {
leftDepth = 1 + maxDepth(root.left);
}
if (root.right != null) {
rightDepth = 1 + maxDepth(root.right);
}
return leftDepth >= rightDepth ? leftDepth : rightDepth;
}
}