/// <summary>
/// Gets all keys that lie along the given path. Does not include the
/// starting point.
/// </summary>
/// <param name="path"></param>
/// <returns></returns>
public HashSet <string> GetKeysAlongPath(IList <GridPoint> path)
{
var result = new HashSet <string>();
for (int i = 0; i < path.Count; i++)
{
var point = path[i];
if (CellsWithKeys.ContainsKey(point))
{
result.Add(CellsWithKeys[point]);
}
}
return(result);
}
private void ConstructMazeGraph()
{
var graphNodes = CellsWithDoors.Select(kvp => kvp.Key)
.ToList();
graphNodes.AddRange(CellsWithKeys.Select(kvp => kvp.Key)
.ToList());
graphNodes.AddRange(StartingPositions);
EdgeShortestPaths = new Dictionary <Tuple <GridPoint, GridPoint>, IList <GridPoint> >();
EdgeKeys = new Dictionary <Tuple <GridPoint, GridPoint>, HashSet <string> >();
IList <GridPoint> GetShortestPathBetweenPoints(GridPoint p1, GridPoint p2)
{
var pathResult = GetPathToPoint(
startPoint: p1,
targetPoint: p2,
keysCollected: new SortedDictionary <string, string>(),
forceAllowToEnterTarget: true);
if (pathResult.Path.Count > 0)
{
var edgeKey12 = new Tuple <GridPoint, GridPoint>(p1, p2);
var edgeKey21 = new Tuple <GridPoint, GridPoint>(p2, p1);
HashSet <string> keysAlongEdge = null;
if (!EdgeShortestPaths.ContainsKey(edgeKey12))
{
keysAlongEdge = GetKeysAlongPath(pathResult.Path);
EdgeShortestPaths.Add(edgeKey12, pathResult.Path);
EdgeKeys.Add(edgeKey12, keysAlongEdge);
}
if (!EdgeShortestPaths.ContainsKey(edgeKey21))
{
var reversedPath = pathResult.Path.ToList();
reversedPath.Reverse();
keysAlongEdge = GetKeysAlongPath(reversedPath);
EdgeShortestPaths.Add(edgeKey21, reversedPath);
EdgeKeys.Add(edgeKey21, keysAlongEdge);
}
}
return(pathResult.Path);
}
MazeGraph = new Graph <GridPoint>(graphNodes, GetShortestPathBetweenPoints);
}
