Leet Code OJ 104. Maximum Depth of Binary Tree [Difficulty: Easy]

题目：
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.

代码实现：

/** * 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;
        }
        int leftnum=0;
        if(root.left!=null){
            leftnum=maxDepth(root.left);
        }
        int rightnum=0;
        if(root.right!=null){
            rightnum=maxDepth(root.right);
        }
        if(leftnum>rightnum){
            return leftnum+1;
        }else{
            return rightnum+1;
        }
    }
}