void setZeroes(vector<vector<int> > &matrix) {

         if (matrix.empty() || matrix[].empty()) return;

         bool firstRow = false;

         bool firstCol = false;

         int m = matrix.size();

         int n = matrix[].size();

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

             if (matrix[i][] == ) {

                 firstCol = true;

                 break;

             }

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

             if (matrix[][j] == ) {

                 firstRow = true;

                 break;

             }

         for (int i = ; i < m; i++) {

             for (int j = ; j < n; j++) {

                 if (matrix[i][j] == ) {

                     matrix[i][] = ;

                     matrix[][j] = ;

                 }

             }

         }

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

             if (matrix[i][] == )

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

                     matrix[i][j] = ;

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

             if (matrix[][j] == )

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

                     matrix[i][j] = ;

         if (firstCol)

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

                 matrix[i][] = ;

         if (firstRow)

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

                 matrix[][j] = ;

 }