void solve() {
   Thread tcThread = new Thread(tc);
   // System.out.println("starting client thread");
   tcThread.start();
   try {
     tcThread.join();
   } catch (Exception e) {
     e.printStackTrace();
   }
   // System.out.println("joined client thread");
   result = SudokuSolver.solve(tc.testcase);
   success = SudokuSolver.isLegalSolution(result, tc.testcase);
 }