// 3. Searching for Single Candidates: Square // "is there a value in any square that is only possible in one location?" public static void SearchSquareForSingleCandidates(this Grid grid) { for (int s = 0; s < grid.GridSize; s++) { for (int value = 1; value <= grid.GridSize; value++) { // that value already exists in the col if (Array.Exists(grid.GetSquare(s), element => element == value)) { continue; } Tuple <int, int> result = grid.CheckSquareForValueInOptions(s, value); if (result.Item1 != -1 && result.Item2 != -1) { grid.SolveCell(result.Item1, result.Item2, value); grid.UpdateNeighbours(result.Item1, result.Item2); } } } }