leetCode-树

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.

题目：

给定二叉树，找到它的最大深度。

最大深度是从根节点到最远叶节点的最长路径上的节点数。

/**
 * Definition for binary tree
 * 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 maxLeft = maxDepth(root.left);
        int maxRight = maxDepth(root.right);
        return maxLeft>maxRight?maxLeft+1:maxRight+1;
    }
}

本题主要用到递归，但首先要判断结点为空的时候，接下来判断左右结点的长度，选出最大的深度