private EightPuzzleResult Solve(PriorityQueue <AStarState> queue)
{
int visitedNodesCount = 0;
while (true)
{
AStarState state = queue.TakeLast();
visitedNodesCount++;
if (state.Board.Equals(Board.FinalBoard))
{
return(new EightPuzzleResult(state, visitedNodesCount));
}
IReadOnlyCollection <Board> neighborBoards = state.Board.GetNeighbors();
foreach (Board board in neighborBoards)
{
if (!WasVisitedPreviously(state, board))
{
AStarState newState = stateFactory.Create(board, state);
queue.Add(newState);
}
}
}
}
private EightPuzzleResult Solve(PriorityQueue <AStarState> queue)
{
HashSet <int> visitedBoardHashes = new HashSet <int>();
int visitedNodesCount = 0;
while (true)
{
AStarState state = queue.TakeLast();
visitedNodesCount++;
if (state.Board.Equals(Board.FinalBoard))
{
return(new EightPuzzleResult(state, visitedNodesCount));
}
IReadOnlyCollection <Board> neighborBoards = state.Board.GetNeighbors();
foreach (Board board in neighborBoards)
{
int boardHash = board.GetHashCode();
if (!visitedBoardHashes.Contains(boardHash))
{
AStarState newState = stateFactory.Create(board, state);
queue.Add(newState);
visitedBoardHashes.Add(boardHash);
}
}
}
}
public AStarStateWithVisitedHashes Create(Board board, AStarStateWithVisitedHashes previousState)
{
AStarState baseState = baseStateFactory.Create(board, previousState);
var hashSet = new HashSet <int>(previousState.VisitedStatesHashes);
hashSet.Add(board.GetHashCode());
return(new AStarStateWithVisitedHashes(baseState, hashSet));
}
public EightPuzzleResult Solve(Board startBoard)
{
AStarState startingState = stateFactory.CreateStartingState(startBoard);
var queue = new PriorityQueue <AStarState>();
queue.Add(startingState);
return(Solve(queue));
}
public AStarStateWithVisitedHashes CreateStartingState(Board startingBoard)
{
AStarState baseState = baseStateFactory.Create(startingBoard, null);
return(new AStarStateWithVisitedHashes(baseState, new HashSet <int>(startingBoard.GetHashCode())));
}
public AStarStateWithVisitedHashes(AStarState baseState, HashSet <int> visitedStatesHashes)
: base(baseState.Board, baseState.PreviousState, baseState.CurrentHeuristicScore, baseState.TotalHeuristicScore)
{
VisitedStatesHashes = visitedStatesHashes;
}