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.

求给定二叉树的最大的深度，最大深度为最远叶子节点到根节点的距离，即根节点到最远叶子节点的距离.

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