#Leetcode# 104. Maximum Depth of Binary Tree

https://leetcode.com/problems/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.

Note: A leaf is a node with no children.

Example:

Given binary tree [3,9,20,null,null,15,7],

    3
   / \
  9  20
    /  \
   15   7

return its depth = 3.

代码：

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    int maxDepth(TreeNode* root) {
        if(!root) return NULL;
        int h1 = 1, h2 = 1;
        if(root -> left != NULL)
            h1 = maxDepth(root -> left) + 1;
        if(root -> right != NULL)
            h2 = maxDepth(root -> right) + 1;
        return max(h1, h2);
    }
};

　　今天是学习各种树的开始