public List <MazeField> Find(TwoDMaze maze)
{
var shortestPath = new ShortestPath <MazeField>();
MazeField start = null, end = null;
foreach (var mazeField in maze.Fields)
{
if (mazeField.FieldType == FieldType.Start)
{
start = mazeField;
}
if (mazeField.FieldType == FieldType.End)
{
end = mazeField;
}
}
var graph = BuildGraphFromMaze(maze);
var startGraphNode = graph.Vertices.First(v => v.Value == start);
var endGraphNode = graph.Vertices.First(v => v.Value == end);
var shortestGraphPath = shortestPath.FindPath(graph, startGraphNode, endGraphNode);
return(shortestGraphPath.Select(p => p.Value).ToList());
}
private TwoDMaze ReadMazeFromString(string mazeString)
{
TwoDMaze maze = new TwoDMaze();
var lines = mazeString.Split(Environment.NewLine).Where(s => !string.IsNullOrEmpty(s)).ToList();
maze.Fields = new MazeField[lines.Count, lines[0].Length];
int i = 0, j = 0;
foreach (var line in lines)
{
j = 0;
foreach (char c in line.ToCharArray())
{
if (c == '0')
{
maze.Fields[i, j] = new MazeField()
{
FieldType = FieldType.Clear, Label = $"{i},{j}"
}
}
;
if (c == 'X')
{
maze.Fields[i, j] = new MazeField()
{
FieldType = FieldType.Obstacle, Label = $"X"
}
}
;
if (c == 'S')
{
maze.Fields[i, j] = new MazeField()
{
FieldType = FieldType.Start, Label = $"S"
}
}
;
if (c == 'E')
{
maze.Fields[i, j] = new MazeField()
{
FieldType = FieldType.End, Label = $"E"
}
}
;
j++;
}
i++;
}
return(maze);
}
public void TestTwoDMazePathFinder()
{
TwoDMazePathFinder mazer = new TwoDMazePathFinder();
string mazeString = @"
S000X
X0X00
X00XX
X0X0E
X0X00
X000X";
TwoDMaze m = ReadMazeFromString(mazeString);
List <MazeField> path = mazer.Find(m);
Assert.Equal(11, path.Count);
}
private IGraph <MazeField> BuildGraphFromMaze(TwoDMaze maze)
{
GraphAdjList <MazeField> graph = new GraphAdjList <MazeField>();
List <Vertex <MazeField> > vertices = new List <Vertex <MazeField> >();
int W = maze.Fields.GetLength(0);
int H = maze.Fields.GetLength(1);
int[] ii = new[] { 0, 0, 1, -1 };
int[] jj = new[] { 1, -1, 0, 0 };
var verticeGrid = new Vertex <MazeField> [W, H];
for (int i = 0; i < W; i++)
{
for (int j = 0; j < H; j++)
{
if (maze.Fields[i, j].FieldType == FieldType.Obstacle)
{
continue;
}
verticeGrid[i, j] = new Vertex <MazeField>()
{
Value = maze.Fields[i, j]
};
}
}
for (int i = 0; i < W; i++)
{
for (int j = 0; j < H; j++)
{
if (maze.Fields[i, j].FieldType == FieldType.Obstacle)
{
continue;
}
for (int step = 0; step < 4; step++)
{
int nextX = i + ii[step];
int nextY = j + jj[step];
if (nextY >= H || nextY < 0)
{
continue;
}
if (nextX >= W || nextX < 0)
{
continue;
}
if (maze.Fields[nextX, nextY].FieldType == FieldType.Clear)
{
Edge <MazeField> edgeTo = new Edge <MazeField>()
{
From = verticeGrid[i, j],
To = verticeGrid[nextX, nextY]
};
Edge <MazeField> edgeFrom = new Edge <MazeField>()
{
To = verticeGrid[i, j],
From = verticeGrid[nextX, nextY]
};
graph.AddEdges(new [] { edgeFrom, edgeTo });
}
}
vertices.Add(verticeGrid[i, j]);
}
}
graph.AddVertices(vertices);
return(graph);
}
