public IActionResult Select([FromForm] ContestProblemViewModel model)
 {
     if (ModelState.IsValid)
     {
         foreach (var item in model.ProblemId)
         {
             var problemContest = new ProblemContest
             {
                 ProblemContestId = Guid.NewGuid(),
                 ContestId        = model.ContestId,
                 ProblemId        = item
             };
             _problemContestRepository.Create(problemContest);
         }
         _problemContestRepository.Save();
         return(RedirectToAction(nameof(Index)));
     }
     return(RedirectToAction(nameof(AddProblems), new { id = model.ContestId }));
 }
 public IActionResult DeleteProblemFromContest([FromForm] ProblemContest contest)
 {
     _problemContestRepository.Delete(contest.ProblemContestId);
     _problemContestRepository.Save();
     return(RedirectToAction(nameof(Index)));
 }