private static IEnumerable <string> ProcessCases(IEnumerable <List <string> > cases) { var currentCaseNumber = 0; foreach (var caseLines in cases) { currentCaseNumber++; //1-indexed. var parsedCase = new CaseInput(caseLines); var solver = new CaseSolver(parsedCase); var result = solver.Solve(); var resultText = result.ToString(); yield return($"Case #{currentCaseNumber}: {resultText}"); } }