[LeetCode]Maximum Depth of Binary Tree

题目描述:(链接)

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.

解题思路：

递归， 深度优先算法！

class Solution {
public:
    int maxDepth(TreeNode* root) {
        if (root == NULL) {
            return 0;
        }
        
        if (root->left == NULL && root->right == NULL) {
            return 1;
        }
        
        int leftDepth = maxDepth(root->left) + 1;
        int rightDepth = maxDepth(root->right) + 1;
        return leftDepth > rightDepth? leftDepth : rightDepth;
    }
};