[leetcode]Populating Next Right Pointers in Each Node II

Follow up for problem "Populating Next Right Pointers in Each Node".
What if the given tree could be any binary tree? Would your previous solution still work?
Note:
You may only use constant extra space.
For example,
Given the following binary tree,
         1
       /  \
      2    3
     / \    \
    4   5    7
After calling your function, the tree should look like:
         1 -> NULL
       /  \
      2 -> 3 -> NULL
     / \    \
    4-> 5 -> 7 -> NULL

还是可以用二叉树的广度优先周游来做。只是必须记录下一行的起始节点用于识别这一行的最后的节点。

/**
 * 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) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if(root == NULL)
            return;
        queue<TreeLinkNode*> Q;
        Q.push(root);
        TreeLinkNode* mostLeft = root;
        bool hasMostLeft = true;
        while(!Q.empty())
        {
            TreeLinkNode* tmp =  Q.front();
            Q.pop();
            if(tmp == mostLeft)
            {
                hasMostLeft = false;
                mostLeft = NULL;
            }
            
            if(tmp->left != NULL)
            {
                Q.push( tmp->left);
                if(hasMostLeft == false)
                {
                    mostLeft = tmp->left;
                    hasMostLeft = true;
                }
            }
            if(tmp->right != NULL)
            {
                Q.push( tmp->right);
                if(hasMostLeft == false)
                {
                    mostLeft = tmp->right;
                    hasMostLeft = true;
                }
            }

            if(Q.empty())
                tmp->next =  NULL;
            else if(Q.front() != mostLeft)
                tmp->next =  Q.front();
            else
                tmp->next =  NULL;
        }
    }
};