【简单】Lintcode 97: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.

Example

Given a binary tree as follow:

  1
 / \ 
2   3
   / \
  4   5

The maximum depth is 3.

解题思路：

    二叉树一般使用递归，把递归函数看作是调用一个复制自己的一个普通函数即可。

/**
 * Definition of TreeNode:
 * class TreeNode {
 * public:
 *     int val;
 *     TreeNode *left, *right;
 *     TreeNode(int val) {
 *         this->val = val;
 *         this->left = this->right = NULL;
 *     }
 * }
 */

class Solution {
public:
    /**
     * @param root: The root of binary tree.
     * @return: An integer
     */
    int maxDepth(TreeNode * root) 
    {
        // write your code here
       if(root==NULL)
           return 0;  

       int left=maxDepth(root->left) + 1;  
       int right=maxDepth(root->right) + 1;  
       return (left>right)?left:right; 
    }
};