public ActionResult Index(int k = 0)
{
int?[,] numbers = new int?[9, 9];
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
string key = string.Format("f{0}{1}", i, j);
int number;
if (int.TryParse(Request[key], out number))
numbers[i, j] = number;
}
}
Game game = new Game(numbers);
Solver solver = new Solver();
try
{
DateTime start = DateTime.Now;
solver.Solve(game);
DateTime end = DateTime.Now;
ViewBag.Interval = string.Format("Solved in {0} ms.", end.Subtract(start).Milliseconds);
}
catch (InvalidGameException)
{
ViewBag.Message = "Invalid entry. There is no solution for the game!";
}
ViewBag.Numbers = game.Numbers;
return View();
}
public void Solve(Game game)
{
bool progress = true;
while (progress && !game.IsSolved)
{
//Console.Out.Write(game);
//Console.Out.WriteLine("");
progress = SolveIteration(game);
if (!progress && !game.IsSolved)
{
progress = SearchSolution(game);
}
}
}
private bool SearchSolution(Game game)
{
// Plan B if SearchIteration doesn't make progress.
// Make a copy of the game, and do a depth first search on possible permutations, until a feasible solution is found.
Stack<Game> gameStack = new Stack<Game>();
gameStack.Push(game);
bool result = SearchSolutionRecursive(gameStack);
Game copy = gameStack.Peek();
var unsolvedTiles = game.GetFlattenedTiles().Where(t => !t.IsSolved);
foreach (Tile tile in unsolvedTiles)
{
tile.Number = copy[tile.XIndex, tile.YIndex].Number;
}
return result;
}
public void TestExpert()
{
int?[,] setup = new int?[,]
{
{ 5, null, 6, null, null, 4, null, null, null },
{ 4, null, null, null, null, null, null, 2, null },
{ null, 2, null, null, null, null, 5, null, 7 },
{ null, null, null, 7, null, 8, null, null, null },
{ null, null, null, null, 3, null, 2, null, 1 },
{ null, null, null, null, null, null, 3, null, null },
{ 1, null, null, 4, null, 2, null, null, 5 },
{ null, null, 4, null, null, 5, 8, null, null },
{ null, null, 3, 6, 8, null, null, null, 2 }
};
Game game = new Game(setup);
Solver solver = new Solver();
solver.Solve(game);
Console.Out.Write(game);
Assert.IsTrue(game.IsSolved);
}
public void TestEasy()
{
int?[,] setup = new int?[,]
{
{ null, null, 9, 1, null, null, null, null, 3 },
{ null, 5, 6, 2, 8, 9, 7, 1, 4 },
{ null, 7, 8, 6, 4, 3, 2, null, null },
{ null, null, 2, null, null, null, 1, null, 9 },
{ null, 3, 7, 5, null, null, 8, null, null },
{ null, 1, 4, 9, null, null, null, 6, null },
{ 8, null, 5, null, null, null, null, null, 1 },
{ 4, 6, 3, null, null, null, null, 2, null },
{ 7, 9, null, null, 5, null, null, null, null }
};
Game game = new Game(setup);
Solver solver = new Solver();
solver.Solve(game);
Console.Out.Write(game);
Assert.IsTrue(game.IsSolved);
}
private bool SolveIteration(Game game)
{
bool tileSolved = false;
IEnumerable<int> allNumbers = new List<int> { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
// The main idea here: first search all tiles and determine if any unsolved tiles are solvable (i.e. we can narrow the candidates to a single number).
// Then walk through all of the numbers and determine if there are any rows, columns, or squares for which that number can fit in only one of the nine tiles.
// Return true if at least one tile is solved this way (so we can try again), false otherwise.
foreach (Tile tile in game.GetFlattenedTiles())
{
if (tile.IsSolved)
continue;
IEnumerable<int> numbers = allNumbers.Except(tile.Row.Numbers)
.Except(tile.Column.Numbers)
.Except(tile.Square.Numbers);
if (numbers.Count() == 0)
{
throw new InvalidGameException();
}
if (numbers.Count() == 1)
{
tile.Number = numbers.First();
tileSolved = true;
}
}
foreach (int number in allNumbers)
{
tileSolved |= SolveForNumber(game.Rows, number);
tileSolved |= SolveForNumber(game.Columns, number);
tileSolved |= SolveForNumber(game.Squares, number);
}
return tileSolved;
}
