leetcode #117 in cpp

Solution:

Similar to #116. Only difference is that we push left or right into queue when left/right is not NULL.

Code:

/**
* Definition for binary tree with next pointer.
* struct TreeLinkNode {
* int val;
* TreeLinkNode *left, *right, *next;
* TreeLinkNode(int x) : val(x), left(NULL), right(NULL), next(NULL) {}
* };
*/
class Solution {
public:
void connect(TreeLinkNode *root) {
if(!root) return;
deque<TreeLinkNode*> que;
que.push_back(root);
while(!que.empty()){
int cap = que.size();
que.push_back(NULL);
while(cap > 0){
TreeLinkNode *temp = que.front();
que.pop_front();
if(temp) temp->next = que.front();
if(temp){
if(temp->left) que.push_back(temp->left);
if(temp->right) que.push_back(temp->right);
}
cap--;
}
que.pop_front();//pop the null at the front
}
return;
}
};