public static void CalculateMinimalDistancesFromGivenPosition(string[,] labyrinth, Position startPosition)
{
Queue<Position> positions = new Queue<Position>();
Queue<int> distances = new Queue<int>();
positions.Enqueue(startPosition);
distances.Enqueue(1);
while (positions.Count != 0)
{
Position currentPosition = positions.Dequeue();
int currentDistance = distances.Dequeue();
for (int i = 0; i < directions.GetLength(0); i++)
{
Position possiblePosition = new Position();
possiblePosition.X = currentPosition.X + directions[i, 0];
possiblePosition.Y = currentPosition.Y + directions[i, 1];
if (IsValidMove(labyrinth, possiblePosition))
{
positions.Enqueue(possiblePosition);
distances.Enqueue(currentDistance + 1);
labyrinth[possiblePosition.X, possiblePosition.Y] = currentDistance.ToString();
}
}
}
FillUnreachableCells(labyrinth);
}
private static void FillLabyrinth(string[,] labyrinth)
{
Position startingPosition = new Position(-1, -1);
for (int i = 0; i < labyrinth.GetLength(0); i++)
{
for (int j = 0; j < labyrinth.GetLength(1); j++)
{
if (labyrinth[i, j] == "*")
{
startingPosition = new Position(i, j);
}
}
}
var queue = new Queue<Position>();
queue.Enqueue(startingPosition);
while (queue.Count != 0)
{
var position = queue.Dequeue();
FillCell(labyrinth, position, queue);
}
FillUnreachableCells(labyrinth);
}
private static void FillCell(string[,] labyrinth, Position position, Queue<Position> queue)
{
var value = 1;
int.TryParse(labyrinth[position.X, position.Y], out value);
if (IsInRange(new Position(position.X + 1, position.Y), labyrinth) && labyrinth[position.X + 1, position.Y] == "0")
{
labyrinth[position.X + 1, position.Y] = (value + 1).ToString();
queue.Enqueue(new Position(position.X + 1, position.Y));
}
if (IsInRange(new Position(position.X, position.Y + 1), labyrinth) && labyrinth[position.X, position.Y + 1] == "0")
{
labyrinth[position.X, position.Y + 1] = (value + 1).ToString();
queue.Enqueue(new Position(position.X, position.Y + 1));
}
if (IsInRange(new Position(position.X - 1, position.Y), labyrinth) && labyrinth[position.X - 1, position.Y] == "0")
{
labyrinth[position.X - 1, position.Y] = (value + 1).ToString();
queue.Enqueue(new Position(position.X - 1, position.Y));
}
if (IsInRange(new Position(position.X, position.Y - 1), labyrinth) && labyrinth[position.X, position.Y - 1] == "0")
{
labyrinth[position.X, position.Y - 1] = (value + 1).ToString();
queue.Enqueue(new Position(position.X, position.Y - 1));
}
}
private static bool OutOfField(Position cellPosition, char[,] labyrinth)
{
if (cellPosition.Column < 0 ||
cellPosition.Column > labyrinth.GetLength(1) - 1 ||
cellPosition.Row < 0 ||
cellPosition.Row > labyrinth.GetLength(0) - 1)
{
return true;
}
return false;
}
public static Position GetStartingPoint(string[,] labyrinth)
{
int rows = labyrinth.GetLength(0);
int cols = labyrinth.GetLength(1);
Position startingPoint = new Position();
for (int row = 0; row < rows; row++)
{
for (int col = 0; col < cols; col++)
{
if (labyrinth[row, col] == "*")
{
startingPoint.X = row;
startingPoint.Y = col;
return startingPoint;
}
}
}
return startingPoint;
}
private static void VisiteCell(char[,] labyrinth, Position visiteCellAtPosition, HashSet<Position> visited, int cellValue, Queue<QueueItem> queue, int[,] resultMovesCount)
{
if (!OutOfField(visiteCellAtPosition, labyrinth)
&& labyrinth[visiteCellAtPosition.Row, visiteCellAtPosition.Column] != 'x'
&& !visited.Contains(visiteCellAtPosition))
{
queue.Enqueue(new QueueItem { Position = visiteCellAtPosition, Value = cellValue });
resultMovesCount[visiteCellAtPosition.Row, visiteCellAtPosition.Column] = cellValue;
visited.Add(visiteCellAtPosition);
}
}
public static void Main()
{
//Test labyrinth
char[,] labyrinth =
{
{'0', '0', '0', 'x', '0', 'x'},
{'0', 'x', '0', 'x', '0', 'x'},
{'0', '*', 'x', '0', 'x', '0'},
{'0', 'x', '0', '0', '0', '0'},
{'0', '0', '0', 'x', 'x', '0'},
{'0', '0', '0', 'x', '0', 'x'}
};
Position player = new Position { Row = 2, Column = 1 };
int[,] resultMoves = new int[labyrinth.GetLength(0), labyrinth.GetLength(1)];
Queue<QueueItem> queue = new Queue<QueueItem>();
HashSet<Position> visited = new HashSet<Position>();
queue.Enqueue(new QueueItem { Position = player, Value = 0 });
visited.Add(player);
while (queue.Count != 0)
{
var cell = queue.Dequeue();
if (OutOfField(cell.Position, labyrinth))
{
continue;
}
Position up = new Position { Row = cell.Position.Row - 1, Column = cell.Position.Column };
Position down = new Position { Row = cell.Position.Row + 1, Column = cell.Position.Column };
Position left = new Position { Column = cell.Position.Column - 1, Row = cell.Position.Row };
Position right = new Position { Column = cell.Position.Column + 1, Row = cell.Position.Row };
VisiteCell(labyrinth, up, visited, cell.Value + 1, queue, resultMoves);
VisiteCell(labyrinth, down, visited, cell.Value + 1, queue, resultMoves);
VisiteCell(labyrinth, left, visited, cell.Value + 1, queue, resultMoves);
VisiteCell(labyrinth, right, visited, cell.Value + 1, queue, resultMoves);
}
char[,] resultLabyrinth = new char[labyrinth.GetLength(0), labyrinth.GetLength(1)];
//Print the result
for (var i = 0; i < resultMoves.GetLength(0); i++)
{
for (var j = 0; j < resultMoves.GetLength(1); j++)
{
if (labyrinth[i, j] == 'x')
{
Console.Write(" X ");
}
else
if (labyrinth[i, j] == '*')
{
Console.Write(" * ");
}
else
{
if (resultMoves[i, j] == 0)
{
Console.Write(" U ");
}
else
{
Console.Write(" " + resultMoves[i, j] + " ");
}
}
}
Console.WriteLine();
}
}
private static bool IsValidMove(string[,] labyrinth, Position position)
{
bool isValidMove = position.X >= 0 && position.X < labyrinth.GetLength(0) &&
position.Y >= 0 && position.Y < labyrinth.GetLength(1) &&
labyrinth[position.X, position.Y] == "0";
return isValidMove;
}
private static bool IsInRange(Position position, string[,] labyrinth)
{
if (position.X > labyrinth.GetLength(0) - 1 || position.X < 0)
{
return false;
}
if (position.Y > labyrinth.GetLength(1) - 1 || position.Y < 0)
{
return false;
}
return true;
}
