class Solution {

 public:

     vector<vector<int> > generate(int numRows) {

         vector<vector<int> > ans;

         if(!numRows) return ans;

         vector<int> tmp;

         tmp.push_back();ans.push_back(tmp);if(numRows==) return ans;

         tmp.push_back();ans.push_back(tmp);if(numRows==) return ans;

         for(int i=; i<numRows; i++)

         {

             tmp.clear();

             tmp.push_back();

             for(int j=; j<i; j++)

             {

                 tmp.push_back( ans[i-][j-]+ans[i-][j] );

             }

             tmp.push_back();

             ans.push_back(tmp);

         }

         return ans;

     }

 };