private void GuessCandidate(PuzzleIterator puzzleIterator, CellValue candidate)
{
var cell = new Cell(candidate.Value);
puzzleIterator.SetCurrent(cell);
ReduceCandidates();
}
private bool SolveCellsRecursively(PuzzleIterator puzzleIterator)
{
if (FindNextUndefinedCell(puzzleIterator))
{
return(TryEachCandidate(puzzleIterator));
}
return(PuzzleIsValid());
}
public bool Solve()
{
var puzzleIterator = new PuzzleIterator(_puzzle);
puzzleIterator.MoveNext();
ReduceCandidates();
return(SolveCellsRecursively(new PuzzleIterator(puzzleIterator)));
}
private bool FindNextUndefinedCell(PuzzleIterator iterator)
{
while (iterator.MoveNext())
{
if (iterator.Current.Value == CellValue.Unknown.Value)
{
return(true);
}
}
return(false);
}
public bool PuzzleIsCompleted()
{
var iterator = new PuzzleIterator(_puzzle);
while (iterator.MoveNext())
{
if (iterator.Current.Value == 0)
{
return(false);
}
}
return(true);
}
private bool TryEachCandidate(PuzzleIterator puzzleIterator)
{
var memento = _puzzle.CreateMemento();
var candidates = puzzleIterator.Current.Candidates;
foreach (var candidate in candidates)
{
_puzzle.SetMemento(memento);
GuessCandidate(puzzleIterator, candidate);
if (PuzzleIsSolved(puzzleIterator))
{
return(true);
}
}
return(false);
}
public void SetUp()
{
var puzzle = new Puzzle(_testPuzzle);
_iterator = new PuzzleIterator(puzzle);
}
private bool PuzzleIsSolved(PuzzleIterator puzzleIterator)
{
return(PuzzleIsValid() && SolveCellsRecursively(new PuzzleIterator(puzzleIterator)));
}
