Binary Tree Level Order Traversal II

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    vector<vector<int>> levelOrderBottom(TreeNode* root) {
        vector<vector<int>> vv;
        vector<int> v;
        queue<TreeNode *>q;
        if(root == NULL) return vv;
      
       
        q.push(root);
       
        int h0=1;
        int h1;
        TreeNode * temp;
        while(!q.empty()){
            h1=0;
            while(h0){
               temp= q.front();
               q.pop();
               v.push_back(temp->val);
           
                if(temp->left){
                    q.push(temp->left);
                    h1++;
                 }
                if(temp->right){
                    q.push(temp->right);
                    h1++;
                }
                h0--;
            }
             vv.push_back(v);
             v.clear();
          
            h0=h1;
        }
        reverse(vv.begin(),vv.end());
        return vv;
    }
};