The maximum depth of the binary tree NO.104

Given a binary tree to find its maximum depth.

The depth of the binary tree is the root node to the nodes on the longest path farthest leaf node.

Description: leaf node is a node has no child nodes.

Example:
given binary tree [3,9,20, null, null, 15,7 ],

    3
   / \
  9  20
    /  \
   15   7

Return to its maximum depth of 3.

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */

int DFS(struct TreeNode* root)
{
    if(!root)return 0;
    int left_depth=0,right_depth=0;
    if(root->left)left_depth=DFS(root->left);
    if(root->right)right_depth=DFS(root->right);
    return left_depth>right_depth?left_depth+1:right_depth+1;
}

int maxDepth(struct TreeNode* root){
    return DFS(root);
}

When execution: 8 ms, beat the 96.93% of all users in C submission

Memory consumption: 9.3 MB, defeated 99.58% of all users in C submission