int solve(int array[9][9])
      {
              int i, j, solved = 0;
               for (i = 0; i <= 8; i++) {
                      for (j = 0; j <= 8; j++) {
                              if (input_number(array, i, j)) {
                                      printf("(%d, %d) => %d\n", i, j, array[i][j]);


                                          } else if (array[i][j] == 0) {
                                      solved = 0;
                              }
                      }
              }
              return solved;
      }

      int solve2(int array[9][9])
      {
              int i, j, solved = 0, solutions = 0;
              while (!solved) {
                      solved = 1;
                      solutions = 0;
                      for (i = 0; i <= 8; i++) {
                              for (j = 0; j <= 8; j++) {
                                      if (input_number(array, i, j)) {
                                              printf("(%d, %d) => %d\n", i, j, array[i][j]);
                                              solutions++;
                                      } else if (array[i][j] == 0) {
                                              solved = 0;
                                      }
                              }
                      }
                      if (solutions == 0)
                              return 0;
              }
              return 1;
      }