【LeetCode】Maximum Depth of Binary Tree (二叉树最大深度)

题目描述：

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.
思路：采用递归的思想，父结点的深度 = max{左右儿子深度} +1

/**
* Definition for binary tree
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int maxDepth(TreeNode *root) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
return func(root);
}
int func(TreeNode *root)
{
if(root == NULL) return 0;
int leftdepth = func(root->left);
int rightdepth =func(root->right);
leftdepth = leftdepth>rightdepth? leftdepth+1:rightdepth+1;
return leftdepth;
}
};