leetcode 104. Maximum Depth of Binary Tree 二叉树的深度

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
int maxDepth(struct TreeNode* root) {
    if(!root)
        return 0;
    int left = 1+maxDepth(root->left);
    int right = 1+maxDepth(root->right);
    return left>right? left:right;
}