/// <summary>
/// Guess a value by forking new puzzle instances.
/// </summary>
private bool Guess()
{
int leastPossibilities = 10;
int bestCandidate = -1;
for (int ci=0; ci<81; ci++) {
Cell cell = Grid.Cells[ci];
if (cell.Value == 0 && cell.Possibilities.Count < leastPossibilities) {
leastPossibilities = cell.Possibilities.Count;
bestCandidate = ci;
}
}
if (bestCandidate > -1) {
foreach(int p in Grid.Cells[bestCandidate].Possibilities) {
Grid newGrid = new Grid();
newGrid.LoadState(Grid.SaveState());
newGrid.Cells[bestCandidate].Value = p;
Puzzle puzzle = new Puzzle(Name, newGrid);
puzzle.SaveStateHistory = SaveStateHistory;
puzzle.Solve("Guess");
if(puzzle.Solved) {
Grid.LoadState(newGrid.SaveState());
State.Concat(puzzle.State);
Solved = true;
return true;
}
}
}
return false;
}