LeetCode--Populating Next Right Pointers in Each Node

 1 /**
 2  * Definition for binary tree with next pointer.
 3  * struct TreeLinkNode {
 4  *  int val;
 5  *  TreeLinkNode *left, *right, *next;
 6  *  TreeLinkNode(int x) : val(x), left(NULL), right(NULL), next(NULL) {}
 7  * };
 8  */
 9 class Solution {
10 public:
11     void connect(TreeLinkNode *root) {
12         if(root == NULL)
13             return;
14         if(root->left != NULL){
15             root->left->next = root->right;
16         }
17         if(root->right != NULL){
18             root->right->next = root->next?root->next->left:NULL;
19         }
20         connect(root->left);
21         connect(root->right);
22     }
23 };