public Puzzle Solve(Puzzle puzzle, SolverContext context, List <CellRange> anchors)
{
bool wordsInserted;
do
{
wordsInserted = false;
foreach (var range in puzzle.PartiallyFilledCellRanges.ToList())
{
var words = puzzle.Words.Where(w => puzzle.Matches(range, w));
if (!words.Any())
{
return(null);
}
if (words.Count() == 1)
{
puzzle = puzzle.SetWord(range, words.Single());
wordsInserted = true;
}
}
} while (wordsInserted);
var part = puzzle.PartiallyFilledCellRanges.ToList();
List <Tuple <string, CellRange> > pairs = new List <Tuple <string, CellRange> >();
foreach (var word in puzzle.Words)
{
foreach (var cellRange in part.Where(p => puzzle.Matches(p, word)))
{
pairs.Add(Tuple.Create(word, cellRange));
}
}
foreach (var pair in OrderPairs(pairs, anchors))
{
var word = pair.Item1;
var range = pair.Item2;
context.count++;
var candidatePuzzle = puzzle.SetWord(range, word);
if (candidatePuzzle == null)
{
continue;
}
if (context.AlreadyTried(candidatePuzzle))
{
continue;
}
//var words = candidatePuzzle.Words.ToArray();
//var ranges = candidatePuzzle.PartiallyFilledCellRanges.Concat(candidatePuzzle.UnfilledCellRanges).ToArray();
//if (words.Length != ranges.Length)
//{
// continue;
//}
if (context.count % 10 == 0)
{
Console.Clear();
Console.WriteLine(candidatePuzzle);
Console.WriteLine($"Solving C:{context.count} D:{context.depth} T:{context.TriedCount}");
}
//foreach (var anchor in anchors)
//{
// var cnt = part.Where(p => p.Overlaps(anchor)).Count();
// Console.WriteLine($"{anchor}: {cnt}");
//}
//if (context.count > 50000)
//{
// Console.ReadKey();
//}
context.depth++;
var solved = Solve(candidatePuzzle, context, anchors.Concat(new[] { range }).ToList());
context.depth--;
if (solved != null)
{
return(solved);
}
if (candidatePuzzle.IsPartialSolution())
{
Console.WriteLine("Rejected partial solution:");
Console.WriteLine(candidatePuzzle);
candidatePuzzle.IsPartialSolution();
Environment.Exit(-1);
}
context.AddTried(candidatePuzzle.CopyOfCells());
}
// No solution is possible
return(null);
}