private IEnumerable <Move> GetAvailableMoves()
{
for (RoomId roomId = 0; roomId != RoomId.Count; roomId++)
{
Room room = Rooms[(int)roomId];
if (room.CanMoveOut)
{
Amphipod occupant = room.Peek();
RoomId destinationRoomId = occupant.Home;
Room destinationRoom = Rooms[(int)destinationRoomId];
if (destinationRoom.CanMoveIn && Hallway.IsRoomReachable(roomId, destinationRoomId, out int hallDistance))
{
yield return(new Move()
{
FromRoom = roomId,
ToRoom = destinationRoomId,
Cost = (room.MoveOutDistance + destinationRoom.MoveInDistance + hallDistance) * occupant.MoveCost,
});
}
else
{
foreach ((HallId hallId, int distance) in Hallway.HallsAvailableFrom(roomId))
{
yield return(new Move()
{
FromRoom = roomId,
ToHall = hallId,
Cost = (room.MoveOutDistance + distance) * occupant.MoveCost,
});
}
}
}
}
for (HallId hallId = 0; hallId < HallId.Count; hallId++)
{
Amphipod?occupantNullable = Hallway.Positions[(int)hallId];
if (occupantNullable.HasValue)
{
Amphipod occupant = occupantNullable.Value;
RoomId roomId = occupant.Home;
Room room = Rooms[(int)roomId];
if (room.CanMoveIn && Hallway.IsRoomReachable(hallId, roomId, out int hallDistance))
{
yield return(new Move()
{
FromHall = hallId,
ToRoom = roomId,
Cost = (hallDistance + room.MoveInDistance) * occupant.MoveCost,
});
}
}
}
}
public Room(Amphipod amphipod, int index, string content)
{
Amphipod = amphipod;
Index = index;
Content = content;
Organized = content.ToCharArray().All(c => c == amphipod.Type);
HasSpace = content.AsSpan().IndexOf('.') != -1;
IsEmptyOrHasAllValidAmphipods = content.ToCharArray().All(c => c == '.' || c == amphipod.Type);
HasAmpipodsOfIncorrectType = !IsEmptyOrHasAllValidAmphipods;
}
static IEnumerable <(int Index, Room Target)> FindAmphipodsInHallway(Board board)
{
for (var i = 0; i < board.Hallway.Length; i++)
{
var c = board.Hallway[i];
if (c is not '.')
{
var room = board.Rooms[Amphipod.Parse(c)];
if (room.IsEmptyOrHasAllValidAmphipods && HallwayPathClear(board.Hallway, i, room.Index))
{
yield return(i, room);
}
}
}
}
internal void Push(Amphipod amphipod)
{
this.canMoveIn = null;
this.isSolved = null;
this.occupants.Push(amphipod);
}