97 Maximum depth of a binary tree

Original title URL: http://www.lintcode.com/zh-cn/problem/maximum-depth-of-binary-tree/#

Given a binary tree, find its maximum depth.

The depth of a binary tree is the distance from the root node to the farthest leaf node.

Have you encountered this question in a real interview? 

Yes

Sample

Given a binary tree as follows:

  1
 / \ 
2   3
   / \
  4   5

The maximum depth of this binary tree is 3.

Label 

Recursive   Binary Tree   Divide and Conquer   Uber   LinkedIn   Apple   Yahoo

 

Ideas: If you have done a balanced binary tree before, this problem is very easy... recursion, the code should not be difficult to understand.

 

AC code:

/**
 * 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 leftDepth=maxDepth(root->left);
     int rightDepth=maxDepth(root->right);
     return max(leftDepth,rightDepth)+1;
    }
};