public ErisMapState Evolve()
{
var cellsAdjacentToBugs = GetAdjacentBugCounts(
out HashSet <GridPoint3D> bugsNotAdjacentToOtherBugs);
// Update cells based on rules
var bugCells = BugCells.ToHashSet();
foreach (var cellAdjacentToBug in cellsAdjacentToBugs)
{
var point = cellAdjacentToBug.Key;
var bugCount = cellAdjacentToBug.Value;
// Each minute, The bugs live and die based on the number of
// bugs in the four adjacent tiles:
// A bug dies(becoming an empty space) unless there is exactly
// one bug adjacent to it.
//An empty space becomes infested with a bug if exactly one or
// two bugs are adjacent to it.
if (!bugCells.Contains(point) &&
(bugCount == 1 ||
bugCount == 2))
{
bugCells.Add(point);
if (MinZ > point.Z)
{
MinZ = point.Z;
}
else if (MaxZ < point.Z)
{
MaxZ = point.Z;
}
}
else if (bugCells.Contains(point) &&
bugCount != 1)
{
bugCells.Remove(point);
}
}
// Kill all bugs not adjacent to other bugs
foreach (var bugPoint in bugsNotAdjacentToOtherBugs)
{
bugCells.Remove(bugPoint);
}
return(new ErisMapState(
bugCells: bugCells,
width: Width,
height: Height,
minZ: MinZ,
maxZ: MaxZ,
isRecursive: IsRecursive));
}
public Dictionary <GridPoint3D, int> GetAdjacentBugCounts(
out HashSet <GridPoint3D> bugsNotAdjacentToOtherBugs)
{
// Build a dictionary of all cells adjacent to bugs
// and count the number of bugs adjacent to them
// If the map is recursive, then add new layers if bugs are
// adjacent to cells in the next inner or outer layer and the
// layers haven't yet been added to the map
var cellsAdjacentToBugs = new Dictionary <GridPoint3D, int>();
bugsNotAdjacentToOtherBugs = BugCells.ToHashSet();
foreach (var bugCell in BugCells)
{
var neighbors = GetNeighbors(bugCell);
foreach (var neighbor in neighbors)
{
if (GetIsPointOffMap(neighbor))
{
// We should only get points off the map if the map is
// not recursive
if (IsRecursive)
{
throw new Exception("Encountered point off map");
}
continue;
}
if (!cellsAdjacentToBugs.ContainsKey(neighbor))
{
cellsAdjacentToBugs.Add(neighbor, 0);
}
cellsAdjacentToBugs[neighbor]++;
if (bugsNotAdjacentToOtherBugs.Contains(neighbor))
{
bugsNotAdjacentToOtherBugs.Remove(neighbor);
}
}
}
return(cellsAdjacentToBugs);
}