public L2Maze(L1Maze maze)
{
// a root is a start point, key or door
var roots = maze.StartPositions.Concat(maze.Keys.Keys.Concat(maze.Doors.Keys)).ToList();
// assign an integer value to each root
var indexMap = roots.Select((root, index) => (root, index)).ToDictionary(t => t.root, t => t.index);
NeighborLookup = roots.Select(r => FindNeighbors(maze, r, indexMap)).ToArray();
AllKeys = maze.AllKeys;
StartPositions = maze.StartPositions.Select(s => indexMap[s]).ToArray();
}
Neighbor[] FindNeighbors(L1Maze maze, (int, int) position, Dictionary <(int, int), int> indexMap)