[leetcode]Maximum Depth of Binary Tree

Maximum Depth of Binary Tree

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. 

算法思路：

递归。没啥说的，常规题。

public class Solution {
    public int maxDepth(TreeNode root) {
        if(root == null) return 0;
        if(root.left == null && root.right == null) return 1;
        int left = 0,right = 0;
        left = maxDepth(root.left);
        right = maxDepth(root.right);
        return Math.max(left,right) + 1;
    }
}