public static int[] CreateClues(SudokuPuzzle input, int maxClues = 0)
{
//Get a unique solution for the input puzzle, in case it wasn't already
var puzzle = input.Solve();
if (puzzle == null) throw new ArgumentException("Can't create clues from an unsolvable puzzle!");
//This is the list of clues we work on. It can be reconstituted into a new puzzle object by way of a constructor
int[] Clues = puzzle.Cells.Select(c => c[0]).ToArray();
var rand = new Random();
while (true)
{
//Pick a random cell to blank
int ClueCell = rand.Next(Clues.Length);
if (Clues[ClueCell] == 0)
continue;
var workingClues = Clues.ToArray();
workingClues[ClueCell] = 0;
if (MultiSolve(new SudokuPuzzle(workingClues), 2).Count() > 1)
{
if (maxClues == 0)
return Clues;
else
continue;
}
Clues = workingClues;
if (Clues.Count(c => c != 0) <= maxClues)
return Clues;
}
}
public static void FindSingularizedCellsTest()
{
var puzzle = new SudokuPuzzle("1234567..........................................................................");
var puzzle2 = puzzle.PlaceValue(7, 8);
var ConstrainedCellIndexes = SudokuPuzzle.FindSingularizedCells(puzzle, puzzle2, 7);
Debug.Assert(ConstrainedCellIndexes.SequenceEqual(new int[] { 8 }));
}
public static void RandomGridTest()
{
var puzzle = SudokuPuzzle.RandomGrid(9);
Debug.Assert(puzzle.Cells.All(c => c.Length == 1));
//var puzzle2 = new SudokuPuzzle(puzzle.Cells.Select(c => c.Single()).ToArray());
}
public static SudokuPuzzle RandomGrid(int size)
{
SudokuPuzzle puzzle = new SudokuPuzzle(size);
var rand = new Random();
while (true)
{
int[] UnsolvedCellIndexes = puzzle.Cells
.Select((cands, index) => new { cands, index }) //Project to a new sequence of candidates and index (an anonymous type behaving like a tuple)
.Where(t => t.cands.Length >= 2) //Filter to cells with at least 2 candidates
.Select(u => u.index) //Project the tuple to only the index
.ToArray();
int cellIndex = UnsolvedCellIndexes[rand.Next(UnsolvedCellIndexes.Length)];
int candidateValue = puzzle.Cells[cellIndex][rand.Next(puzzle.Cells[cellIndex].Length)];
SudokuPuzzle workingPuzzle = puzzle.PlaceValue(cellIndex, candidateValue);
if (workingPuzzle != null)
{
var Solutions = MultiSolve(workingPuzzle, 2);
switch (Solutions.Count)
{
case 0: continue;
case 1: return(Solutions.Single());
default:
puzzle = workingPuzzle;
break;
}
}
}
}
public static void TestPeers()
{
var p = new SudokuPuzzle(9);
var peers = p.Peers(40);
var expectedResult = new int[] { 4, 13, 22, 30, 31, 32, 36, 37, 38, 39, 41, 42, 43, 44, 48, 49, 50, 58, 67, 76 };
Debug.Assert(peers.SequenceEqual(expectedResult));
}
public static void FindSingularizedCellsTest()
{
var puzzle = new SudokuPuzzle("1234567..........................................................................");
var puzzle2 = puzzle.PlaceValue(7, 8);
var ConstrainedCellIndexes = SudokuPuzzle.FindSingularizedCells(puzzle, puzzle2, 7);
Debug.Assert(ConstrainedCellIndexes.SequenceEqual(new int[] { 8 }));
}
public static void MultiSolveTest()
{
var puzzle = new SudokuPuzzle(" 456789679813245548927136 594678857361492964782513 648957796135824485279361");
var solutions = SudokuPuzzle.MultiSolve(puzzle);
Debug.Assert(solutions.Count() == 12);
solutions = SudokuPuzzle.MultiSolve(puzzle, 2);
Debug.Assert(solutions.Count() == 2);
}
public static void MultiSolveTest()
{
var puzzle = new SudokuPuzzle(" 456789679813245548927136 594678857361492964782513 648957796135824485279361");
var solutions = SudokuPuzzle.MultiSolve(puzzle);
Debug.Assert(solutions.Count() == 12);
solutions = SudokuPuzzle.MultiSolve(puzzle, 2);
Debug.Assert(solutions.Count() == 2);
}
public static void ApplyConstraintsTest()
{
int cell = 0;
int value = 1;
var puzzle = new SudokuPuzzle(9).ApplyConstraints(cell, value);
Debug.Assert(puzzle.Cells[cell].Single() == value);
foreach (int peerIndex in puzzle.Peers(cell))
Debug.Assert(!puzzle.Cells[peerIndex].Contains(value));
}
public static List <SudokuPuzzle> MultiSolve(SudokuPuzzle input, int MaximumSolutions = -1)
{
var Solutions = new List <SudokuPuzzle>();
input.Solve(p =>
{
Solutions.Add(p);
return(Solutions.Count() < MaximumSolutions || MaximumSolutions == -1);
});
return(Solutions);
}
public static void ApplyConstraintsTest()
{
int cell = 0;
int value = 1;
var puzzle = new SudokuPuzzle(9).ApplyConstraints(cell, value);
Debug.Assert(puzzle.Cells[cell].Single() == value);
foreach (int peerIndex in puzzle.Peers(cell))
{
Debug.Assert(!puzzle.Cells[peerIndex].Contains(value));
}
}
public virtual object Clone()
{
var clone = new SudokuPuzzle(this.Length);
clone.Cells = new int[this.Cells.Length][];
for (int i = 0; i < this.Cells.Length; i++)
{
clone.Cells[i] = new int[this.Cells[i].Length];
Buffer.BlockCopy(this.Cells[i], 0, clone.Cells[i], 0, Buffer.ByteLength(this.Cells[i]));
}
return(clone);
}
public static List <int> FindSingularizedCells(SudokuPuzzle puzzle1, SudokuPuzzle puzzle2, int cellIndex)
{
Debug.Assert(puzzle1.Length == puzzle2.Length);
var result = new List <int>();
foreach (int i in puzzle1.Peers(cellIndex))
{
if (puzzle1.Cells[i].Length > 1 && puzzle2.Cells[i].Length == 1)
{
result.Add(i);
}
}
return(result);
}
public static void SimpleTest()
{
var p = new SudokuPuzzle(TestPuzzle);
p = p.Solve();
Debug.Assert(p.Cells.Select(c => c[0]).SequenceEqual(new int[] {
4, 8, 3, 9, 2, 1, 6, 5, 7,
9, 6, 7, 3, 4, 5, 8, 2, 1,
2, 5, 1, 8, 7, 6, 4, 9, 3,
5, 4, 8, 1, 3, 2, 9, 7, 6,
7, 2, 9, 5, 6, 4, 1, 3, 8,
1, 3, 6, 7, 9, 8, 2, 4, 5,
3, 7, 2, 6, 8, 9, 5, 1, 4,
8, 1, 4, 2, 5, 3, 7, 6, 9,
6, 9, 5, 4, 1, 7, 3, 8, 2
}));
}
public static void SimpleTest2()
{
var p = new SudokuPuzzle("53..7....6..195....98....6.8...6...34..8.3..17...2...6.6....28....419..5....8..79");
p = p.Solve();
Debug.Assert(p.Cells.Select(c => c[0]).SequenceEqual(new int[] {
5, 3, 4, 6, 7, 8, 9, 1, 2,
6, 7, 2, 1, 9, 5, 3, 4, 8,
1, 9, 8, 3, 4, 2, 5, 6, 7,
8, 5, 9, 7, 6, 1, 4, 2, 3,
4, 2, 6, 8, 5, 3, 7, 9, 1,
7, 1, 3, 9, 2, 4, 8, 5, 6,
9, 6, 1, 5, 3, 7, 2, 8, 4,
2, 8, 7, 4, 1, 9, 6, 3, 5,
3, 4, 5, 2, 8, 6, 1, 7, 9
}));
}
public static void SimpleTest()
{
var p = new SudokuPuzzle(TestPuzzle);
p = p.Solve();
Debug.Assert(p.Cells.Select(c => c[0]).SequenceEqual(new int[] {
4, 8, 3, 9, 2, 1, 6, 5, 7,
9, 6, 7, 3, 4, 5, 8, 2, 1,
2, 5, 1, 8, 7, 6, 4, 9, 3,
5, 4, 8, 1, 3, 2, 9, 7, 6,
7, 2, 9, 5, 6, 4, 1, 3, 8,
1, 3, 6, 7, 9, 8, 2, 4, 5,
3, 7, 2, 6, 8, 9, 5, 1, 4,
8, 1, 4, 2, 5, 3, 7, 6, 9,
6, 9, 5, 4, 1, 7, 3, 8, 2
}));
}
public static void SimpleTest2()
{
var p = new SudokuPuzzle("53..7....6..195....98....6.8...6...34..8.3..17...2...6.6....28....419..5....8..79");
p = p.Solve();
Debug.Assert(p.Cells.Select(c => c[0]).SequenceEqual(new int[] {
5, 3, 4, 6, 7, 8, 9, 1, 2,
6, 7, 2, 1, 9, 5, 3, 4, 8,
1, 9, 8, 3, 4, 2, 5, 6, 7,
8, 5, 9, 7, 6, 1, 4, 2, 3,
4, 2, 6, 8, 5, 3, 7, 9, 1,
7, 1, 3, 9, 2, 4, 8, 5, 6,
9, 6, 1, 5, 3, 7, 2, 8, 4,
2, 8, 7, 4, 1, 9, 6, 3, 5,
3, 4, 5, 2, 8, 6, 1, 7, 9
}));
}
public static int[] CreateClues(SudokuPuzzle input, int maxClues = 0)
{
//Get a unique solution for the input puzzle, in case it wasn't already
var puzzle = input.Solve();
if (puzzle == null)
{
throw new ArgumentException("Can't create clues from an unsolvable puzzle!");
}
//This is the list of clues we work on. It can be reconstituted into a new puzzle object by way of a constructor
int[] Clues = puzzle.Cells.Select(c => c[0]).ToArray();
var rand = new Random();
while (true)
{
//Pick a random cell to blank
int ClueCell = rand.Next(Clues.Length);
if (Clues[ClueCell] == 0)
{
continue;
}
var workingClues = Clues.ToArray();
workingClues[ClueCell] = 0;
if (MultiSolve(new SudokuPuzzle(workingClues), 2).Count() > 1)
{
if (maxClues == 0)
{
return(Clues);
}
else
{
continue;
}
}
Clues = workingClues;
if (Clues.Count(c => c != 0) <= maxClues)
{
return(Clues);
}
}
}
public virtual SudokuPuzzle ApplyConstraints(int cellIndex, int value)
{
SudokuPuzzle puzzle = (SudokuPuzzle)this.Clone();
//Standard Sudoku constraint logic: Set this cell to one and only one candidate, and remove this value from the candidate list of all its peers
puzzle.Cells[cellIndex] = new int[] { value };
foreach (int peerIndex in puzzle.Peers(cellIndex))
{
var newPeers = puzzle.Cells[peerIndex].Except(new int[] { value }).ToArray();
if (!newPeers.Any())
{
return(null);
}
puzzle.Cells[peerIndex] = newPeers;
}
return(puzzle);
}
public static void Top95TimedTest()
{
var stream = new StreamReader("top95.txt");
var puzzles = new List <String>();
while (!stream.EndOfStream)
{
puzzles.Add(stream.ReadLine());
}
stream.Close();
var times = puzzles.Select(p =>
{
DateTime start = DateTime.Now;
var puz = new SudokuPuzzle(p).Solve();
SudokuPuzzle.Output(puz);
return(DateTime.Now - start);
}).ToList();
Console.WriteLine("Average: " + times.Average(ts => ts.TotalSeconds));
Console.WriteLine("Worst: " + times.Max(ts => ts.TotalSeconds));
}
public static List<int> FindSingularizedCells(SudokuPuzzle puzzle1, SudokuPuzzle puzzle2, int cellIndex)
{
Debug.Assert(puzzle1.Length == puzzle2.Length);
var result = new List<int>();
foreach (int i in puzzle1.Peers(cellIndex))
{
if (puzzle1.Cells[i].Length > 1 && puzzle2.Cells[i].Length == 1)
result.Add(i);
}
return result;
}
public static void RandomGridTest()
{
var puzzle = SudokuPuzzle.RandomGrid(9);
Debug.Assert(puzzle.Cells.All(c => c.Length == 1));
var puzzle2 = new SudokuPuzzle(puzzle.Cells.Select(c => c.Single()).ToArray());
}
public static void Output(SudokuPuzzle puzzle)
{
System.Console.Write(puzzle.ToString());
}
public static List<SudokuPuzzle> MultiSolve(SudokuPuzzle input, int MaximumSolutions = -1)
{
var Solutions = new List<SudokuPuzzle>();
input.Solve(p =>
{
Solutions.Add(p);
return Solutions.Count() < MaximumSolutions || MaximumSolutions == -1;
});
return Solutions;
}
public static SudokuPuzzle RandomGrid(int size)
{
SudokuPuzzle puzzle = new SudokuPuzzle(size);
var rand = new Random();
while (true)
{
int[] UnsolvedCellIndexes = puzzle.Cells
.Select((cands, index) => new { cands, index }) //Project to a new sequence of candidates and index (an anonymous type behaving like a tuple)
.Where(t => t.cands.Length >= 2) //Filter to cells with at least 2 candidates
.Select(u => u.index) //Project the tuple to only the index
.ToArray();
int cellIndex = UnsolvedCellIndexes[rand.Next(UnsolvedCellIndexes.Length)];
int candidateValue = puzzle.Cells[cellIndex][rand.Next(puzzle.Cells[cellIndex].Length)];
SudokuPuzzle workingPuzzle = puzzle.PlaceValue(cellIndex, candidateValue);
if (workingPuzzle != null)
{
var Solutions = MultiSolve(workingPuzzle, 2);
switch (Solutions.Count)
{
case 0: continue;
case 1: return Solutions.Single();
default:
puzzle = workingPuzzle;
break;
}
}
}
}
public virtual object Clone()
{
var clone = new SudokuPuzzle(this.Length);
clone.Cells = new int[this.Cells.Length][];
for (int i = 0; i < this.Cells.Length; i++)
{
clone.Cells[i] = new int[this.Cells[i].Length];
Buffer.BlockCopy(this.Cells[i], 0, clone.Cells[i], 0, Buffer.ByteLength(this.Cells[i]));
}
return clone;
}
public static void TestPeers()
{
var p = new SudokuPuzzle(9);
var peers = p.Peers(40);
var expectedResult = new int[] { 4, 13, 22, 30, 31, 32, 36, 37, 38, 39, 41, 42, 43, 44, 48, 49, 50, 58, 67, 76 };
Debug.Assert(peers.SequenceEqual(expectedResult));
}
public static void Output(SudokuPuzzle puzzle)
{
System.Console.Write(puzzle.ToString());
}
public static void Top95TimedTest()
{
var stream = new StreamReader("top95.txt");
var puzzles = new List<String>();
while (!stream.EndOfStream)
puzzles.Add(stream.ReadLine());
stream.Close();
var times = puzzles.Select(p =>
{
DateTime start = DateTime.Now;
var puz = new SudokuPuzzle(p).Solve();
SudokuPuzzle.Output(puz);
return (DateTime.Now - start);
}).ToList();
Console.WriteLine("Average: " + times.Average(ts => ts.TotalSeconds));
Console.WriteLine("Worst: " + times.Max(ts => ts.TotalSeconds));
}