private static void Solve(PuzzleSetup puzzleSetup)
{
IncorrectGuesses = new Dictionary <int, Candidates>();
for (var i = 0; i < 81; i++)
{
IncorrectGuesses[i] = Candidates.None;
}
var puzzle = new PuzzleGrid(puzzleSetup);
foreach (var cell in puzzle.Cells)
{
cell.Initialize();
}
puzzle.Print();
bool solved;
var result = Solve(puzzle, out solved);
Console.WriteLine(solved ? "Solved!" : "Failed");
result.Print();
}
private static PuzzleGrid Solve(PuzzleGrid puzzle, out bool solved)
{
var anyChanges = false;
do
{
anyChanges = false;
var unsolvedCells = puzzle.Cells
.Where(c => !c.Solution.HasValue)
.ToArray();
if (!unsolvedCells.Any())
{
solved = true;
return(puzzle);
}
if (anyChanges |= unsolvedCells.TrySingleCandidateSolve())
{
Console.WriteLine("Single candidate.");
continue;
}
if (anyChanges |= unsolvedCells.TryUniqueCandidateSolve())
{
Console.WriteLine("Unique candidate.");
continue;
}
if (anyChanges |= puzzle.Boxes.TryCandidateLineElimination())
{
Console.WriteLine("Candidate line.");
continue;
}
if (anyChanges |= puzzle.AllUnits.TryNakedPairElimination())
{
Console.WriteLine("Naked pair.");
continue;
}
if (anyChanges |= puzzle.AllUnits.TryNakedTripleElimination())
{
Console.WriteLine("Naked triple.");
continue;
}
if (anyChanges |= puzzle.AllUnits.TryNakedQuadElimination())
{
Console.WriteLine("Naked quadruple.");
continue;
}
if (anyChanges |= puzzle.AllUnits.TryNakedQuintElimination())
{
Console.WriteLine("Naked quintuplet.");
continue;
}
if (anyChanges |= puzzle.TryDoublePairElimination())
{
Console.WriteLine("Double pair.");
continue;
}
if (anyChanges |= puzzle.TryClosedLoopCandidateElimination(loopScale: 2))
{
Console.WriteLine("X-Wing.");
continue;
}
if (anyChanges |= puzzle.TryClosedLoopCandidateElimination(loopScale: 3))
{
Console.WriteLine("Swordfish.");
continue;
}
if (anyChanges |= puzzle.TryClosedLoopCandidateElimination(loopScale: 4))
{
Console.WriteLine("Closed loop, scale 4.");
continue;
}
if (anyChanges |= puzzle.TryClosedLoopCandidateElimination(loopScale: 5))
{
Console.WriteLine("Closed loop, scale 5.");
continue;
}
//var mostSolvedCellIdx = unsolvedCells
// .OrderBy(c => c.Candidates.CountExcluding(IncorrectGuesses[c.Idx]))
// .First()
// .Idx;
//var clone = puzzle.DeepClone();
//var cell = clone.Cells[mostSolvedCellIdx];
//var nextGuess = cell.Candidates.FirstOrDefaultExcluding(IncorrectGuesses[mostSolvedCellIdx]);
//if(nextGuess == Candidates.None)
//{
// throw new InvalidOperationException($"No remaining guesses for cell {mostSolvedCellIdx}");
//}
//Console.WriteLine($"Guessing {nextGuess} on cell {cell.Idx}");
//cell.Solve(nextGuess);
//try
//{
// Solve(clone, out solved);
// if (solved)
// {
// return clone;
// }
// anyChanges = true;
//}
//catch (InvalidSolutionException)
//{
// Console.WriteLine("Incorrect guess.");
// IncorrectGuesses[mostSolvedCellIdx] |= nextGuess;
// solved = false;
// return clone;
//}
}while (anyChanges);
solved = false;
return(puzzle);
}
public static bool ClosedLoop(
this PuzzleGrid puzzle,
byte loopScale,
Func <PuzzleGrid, Cell[][]> getUnits, // row or cols
Func <PuzzleGrid, Cell[][]> getOtherUnits, // cols or rows
Func <Cell, byte> getIdxInOtherUnit) // RowIdx or ColIdx
{
var anyChanges = false;
foreach (var candidate in CandidatesUtil.ALL)
{
var indiciesOfCandidateWithinUnits = new Dictionary <int, Index>();
for (var i = 0; i < 9; i++)
{
Index indicies;
if (GetIndiciesOfCandidateIfOccuringTwice(getUnits(puzzle)[i], candidate, out indicies))
{
indiciesOfCandidateWithinUnits.Add(i, indicies);
}
}
if (indiciesOfCandidateWithinUnits.Count < loopScale)
{
continue;
}
var unitCount = indiciesOfCandidateWithinUnits.Count;
var unitIdxGroups = indiciesOfCandidateWithinUnits.Select(i => i.Key).ToList().UniqueCombinations(loopScale);
foreach (var unitIdxGroup in unitIdxGroups)
{
var units = indiciesOfCandidateWithinUnits
.Where(i => unitIdxGroup.Contains(i.Key))
.ToArray();
var indicies = Index.None;
foreach (var index in units.Select(u => u.Value))
{
indicies |= index;
}
if (!indicies.HasNumberOfIndicies(loopScale))
{
continue;
}
foreach (var unitIndexAndCellIndiciesPair in indiciesOfCandidateWithinUnits)
{
var unitIdx = unitIndexAndCellIndiciesPair.Key;
var indexesInUnit = unitIndexAndCellIndiciesPair.Value.GetValues()
.Select(idx => IndexUtil.INDEX_BYTE_MAP[idx])
.ToArray();
var cell1 = getUnits(puzzle)[unitIdx][indexesInUnit[0]];
var cell2 = getUnits(puzzle)[unitIdx][indexesInUnit[1]];
foreach (var cell in getOtherUnits(puzzle)[getIdxInOtherUnit(cell1)])
{
if (cell == cell1 || cell == cell2)
{
continue;
}
anyChanges |= cell.RemoveCandidates(candidate);
}
}
}
}
return(anyChanges);
}
