public Cell(int row, int col, char value, Cell predecessor)
{
this.row = row;
this.col = col;
this.value = value;
this.predecessor = predecessor;
}
public bool ContainsCell(Cell cell)
{
if (cells.Contains(cell))
{
return true;
}
else
{
return false;
}
}
public Path(Cell exitCell)
{
cells = new List<Cell>();
Cell current = exitCell;
while (current != null)
{
cells.Add(current);
current = current.Predecessor;
}
cells.Reverse();
}
public Cell GetTopNeighbour(Cell current)
{
if (current.Row - 1 < 0)
{
return null;
}
return maze[current.Row - 1, current.Column];
}
public Cell GetRightNeighbour(Cell current)
{
if (current.Column + 1 >= maze.GetLength(1))
{
return null;
}
return maze[current.Row, current.Column + 1];
}
public Cell GetLeftNeighbour(Cell current)
{
if (current.Column - 1 < 0)
{
return null; // indicates reaching an exit
}
return maze[current.Row, current.Column - 1];
}
public Cell GetBottomNeighbour(Cell current)
{
if (current.Row + 1 == maze.GetLength(0))
{
return null;
}
return maze[current.Row + 1, current.Column];
}
public List<Path> FindAllPaths()
{
paths = new List<Path>();
Queue<Cell> queue = new Queue<Cell>();
queue.Enqueue(startingPos);
while (queue.Count > 0)
{
Cell current = queue.Dequeue();
Cell leftNeighbour = GetLeftNeighbour(current);
if (leftNeighbour == null)
{
Path newPath = new Path(current);
if (!paths.Contains(newPath))
paths.Add(newPath);
}
else if (leftNeighbour.Value != '#')
{
Cell leftNeighbourUpdated = new Cell(leftNeighbour.Row, leftNeighbour.Column,
leftNeighbour.Value, current);
if (!current.HasPredecessor(leftNeighbourUpdated)) // if not already has predecessor
{
queue.Enqueue(leftNeighbourUpdated);
}
}
Cell topNeighbour = GetTopNeighbour(current);
if (topNeighbour == null)
{
Path newPath = new Path(current);
if (!paths.Contains(newPath))
paths.Add(newPath);
}
else if (topNeighbour.Value != '#')
{
Cell topNeighbourUpdated = new Cell(topNeighbour.Row, topNeighbour.Column,
topNeighbour.Value, current);
if (!current.HasPredecessor(topNeighbourUpdated))
{
queue.Enqueue(topNeighbourUpdated);
}
}
Cell rightNeighbour = GetRightNeighbour(current);
if (rightNeighbour == null)
{
Path newPath = new Path(current);
if (!paths.Contains(newPath))
paths.Add(newPath);
}
else if (rightNeighbour.Value != '#')
{
Cell rightNeighbourUpdated = new Cell(rightNeighbour.Row, rightNeighbour.Column,
rightNeighbour.Value, current);
if (!current.HasPredecessor(rightNeighbourUpdated))
{
queue.Enqueue(rightNeighbourUpdated);
}
}
Cell bottomNeighbour = GetBottomNeighbour(current);
if (bottomNeighbour == null)
{
Path newPath = new Path(current);
if (!paths.Contains(newPath))
paths.Add(newPath);
}
else if (bottomNeighbour.Value != '#')
{
Cell bottomNeighbourUpdated = new Cell(bottomNeighbour.Row, bottomNeighbour.Column,
bottomNeighbour.Value, current);
if (!current.HasPredecessor(bottomNeighbourUpdated))
{
queue.Enqueue(bottomNeighbourUpdated);
}
}
}
return paths;
}
public Maze(string filePath)
{
if (!File.Exists(filePath))
{
throw new FileNotFoundException(String.Format("File \"{0}\" was not found.", filePath));
}
StreamReader reader = new StreamReader(filePath);
startingPos = null;
int size = int.Parse(reader.ReadLine()); // it's always in the first line by definition
this.maze = new Cell[size, size];
for (int i = 0; i < size; i++)
{
string line = reader.ReadLine();
for (int p = 0; p < line.Length; p += 2)
{
maze[i, p / 2] = new Cell(i, p / 2, line[p], null);
if (line[p] == '*')
{
startingPos = maze[i, p / 2];
}
}
}
if (startingPos == null)
{
throw new Exception("No staring posiiton in the maze.");
}
reader.Close();
}
public bool HasPredecessor(Cell other)
{
Path pathSoFar = new Path(this);
if (pathSoFar.ContainsCell(other))
{
return true;
}
else
{
return false;
}
}