maximum-depth-of-binary-tree——找出数的最大深度

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.

/**
 * 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) {
        if(root==NULL) return 0;
        if(root->left==NULL&&root->right==NULL) return 1;
        return max(maxDepth(root->left),maxDepth(root->right))+1;
    }
};