public static List <string> PlanB(State state, bool debug, Func <StateMetadata, bool> terminatingCondition)
{
string moves = "WASD";
var transpositionTable = new HashSet <Point>()
{
state.Position
};
var priorityQueue = new PriorityQueue <StateMetadata>((rhs, lhs) =>
lhs.Depth == rhs.Depth ? CompareMetadata(lhs, rhs) : lhs.Depth < rhs.Depth);
var initialState = new StateMetadata()
{
State = state
};
priorityQueue.Push(initialState);
while (!priorityQueue.IsEmpty())
{
var currentMetadata = priorityQueue.Pop();
var currentBoard = currentMetadata.State.Board;
var currentPosition = currentMetadata.State.Position;
if (terminatingCondition(currentMetadata))
{
return(currentMetadata.ToList().Select(i => i.Move).ToList());
}
foreach (var move in moves)
{
var newState = currentMetadata.State.Move(move);
if (newState != null)
{
var newMetadata = new StateMetadata()
{
State = newState.Item1,
Depth = currentMetadata.Depth + 1,
Move = move.ToString(),
PreviousState = currentMetadata
};
newMetadata.State.Board.Undo(newState.Item2);
if (!transpositionTable.Contains(newState.Item1.Position))
{
priorityQueue.Push(newMetadata);
transpositionTable.Add(newMetadata.State.Position);
}
}
}
}
return(null);
}
private static bool CompareMetadata(StateMetadata lhs, StateMetadata rhs)
{
foreach (var metric in GetMetrics(lhs).Zip(GetMetrics(rhs), (l, r) => l - r))
{
if (metric != 0)
{
return(metric < 0);
}
}
return(false);
}
public static List <string> PlanA(State state, bool debug)
{
var middle = new Point(state.Board.MaxX / 2, state.Board.MaxY / 2);
string moves = "FWASDQE";
StateMetadata bestMove = null;
var metadata = new StateMetadata()
{
State = state, Redo = new BoardUndo(), Debug = state.Board.Clone()
};
var transpositionTable = new Dictionary <object, StateMetadata>()
{
{ state.GetHashTuple(), metadata }
};
var priorityQueue = new PriorityQueue <StateMetadata>((rhs, lhs) =>
lhs.Depth == rhs.Depth ? CompareMetadata(lhs, rhs) : lhs.Depth < rhs.Depth);
priorityQueue.Push(metadata);
while (!priorityQueue.IsEmpty())
{
var currentMetadata = priorityQueue.Pop();
if (bestMove != null && bestMove.State.UnpaintedCount == 0 ||
currentMetadata.Depth >= MaxDepth)
{
if (bestMove.State.UnpaintedCount == state.UnpaintedCount)
{
return(null);
}
return(bestMove.ToList().Select(i => i.Move).ToList());
}
var undoBase = currentMetadata.State.Board.Redo(currentMetadata.Redo);
//currentMetadata.State.Board.Compare(currentMetadata.Debug);
foreach (var move in moves.Where(m => currentMetadata.Depth == 0 || m != 'F' && m != 'L'))
{
var afterMove = currentMetadata.State.Move(move);
if (afterMove != null)
{
var newState = afterMove.Item1;
var undoMove = afterMove.Item2;
var newPoints = undoMove == null ? 0 : undoMove.Points.Sum(p => 1 + GetWallCount(state.Board, p.Item1));
var newMetadata = new StateMetadata()
{
Score = currentMetadata.Score + newPoints,
State = newState,
Depth = currentMetadata.Depth + 1,
Move = move.ToString(),
PreviousState = currentMetadata
};
var isBetterMove = bestMove == null || CompareMetadata(newMetadata, bestMove);
if (isBetterMove)
{
bestMove = newMetadata;
}
if (debug)
{
var betterMoveString = isBetterMove ? " *" : "";
if (isBetterMove)
{
Console.WriteLine($"{newMetadata}{betterMoveString}");
}
}
if (!transpositionTable.ContainsKey(newState.GetHashTuple()))
{
//newMetadata.Debug = state.Board.Clone();
newMetadata.Redo = new BoardUndo();
newMetadata.Redo.Points.AddRange(currentMetadata.Redo.Points);
newMetadata.Redo.Points.AddRange(state.Board.GetRedo(undoMove).Points);
priorityQueue.Push(newMetadata);
transpositionTable[newMetadata.State] = null;
}
currentMetadata.State.Board.Undo(undoMove);
}
}
currentMetadata.State.Board.Undo(undoBase);
}
throw new Exception("No moves found");
}
// Heuristics:
// Maximize boosts collected.
// Maximize score unpainted squares.
//
private static IEnumerable <int> GetMetrics(StateMetadata metadata)
{
yield return(-metadata.State.BoostsCollected);
yield return(-metadata.Score);
}
