leetcode116

class Solution {
public:
    void connect(TreeLinkNode *root) {
        if (root != NULL)
        {
            queue<TreeLinkNode*> Q;
            root->next = NULL;
            Q.push(root);
            while (!Q.empty())
            {
                vector<TreeLinkNode*> V;
                while (!Q.empty())
                {
                    TreeLinkNode* t = Q.front();
                    Q.pop();
                    if (t->left != NULL)
                    {
                        V.push_back(t->left);
                    }
                    if (t->right != NULL)
                    {
                        V.push_back(t->right);
                    }
                }
                V.push_back(NULL);
                for (int i = V.size() - 1; i > 0; i--)
                {
                    V[i - 1]->next = V[i];
                }
                for (int i = 0; i < V.size() - 1; i++)
                {
                    if (V[i] != NULL)
                    {
                        Q.push(V[i]);
                    }
                }
            }
        }
    }
};