public List <Tile> AdjacentTiles(Tile tile, bool addIfMissing = true)
{
// directions of neighbour
List <(int x, int y)> neighboursIndex = new List <(int x, int y)>()
{
(1, 0), (1, -1), (0, -1), (-1, 0), (-1, 1), (0, 1)
};
// e = y: same, x: +1
// se = y: -1, x: +1
// sw = y: -1, x: same
// w = y: same, x: -1
// nw = y: 1, x: -1
// ne = y: 1, x: same
var neighbours = new List <Tile>();
foreach (var item in neighboursIndex)
{
int x = item.x + tile.x;
int y = item.y + tile.y;
if (TilesVisited.ContainsKey($"{x},{y}"))
{
neighbours.Add(TilesVisited[$"{x},{y}"]);
}
else if (!NewTiles.ContainsKey($"{x},{y}") && addIfMissing)
{
NewTiles.Add($"{x},{y}", new Tile(x, y));
}
}
return(neighbours);
}
public void Run2(int days = 10)
{
Run();
// start to execute days of flipping
for (int day = 1; day <= days; day++)
{
// Any black tile with zero or more than 2 black tiles immediately adjacent to it is flipped to white.
// Any white tile with exactly 2 black tiles immediately adjacent to it is flipped to black.
foreach (var(ind, tile) in TilesVisited)
{
var adjacent = AdjacentTiles(tile);
var blackAdjacent = adjacent.Where((item) => !item.White).Count();
if (tile.White && blackAdjacent == 2)
{
// exactly 2 black tiles, flip to black!
tile.FlipTo = false;
}
else if (!tile.White && (blackAdjacent == 0 || blackAdjacent > 2))
{
tile.FlipTo = true;
}
}
foreach (var(ind, tile) in NewTiles)
{
TilesVisited.Add(tile.Index, tile);
var adjacent = AdjacentTiles(tile, false);
var blackAdjacent = adjacent.Where((item) => !item.White).Count();
if (tile.White && blackAdjacent == 2)
{
// exactly 2 black tiles, flip to black!
tile.FlipTo = false;
}
else if (!tile.White && (blackAdjacent == 0 || blackAdjacent > 2))
{
tile.FlipTo = true;
}
}
foreach (var(ind, tile) in TilesVisited)
{
tile.ExecuteFlip();
}
NewTiles = new Dictionary <string, Tile>();
var nr = CountBlackTiles();
// Console.WriteLine($"Day {day}: {nr}");
}
}
public void Run()
{
// convert the steps to a x and y position
// https://gamedev.stackexchange.com/a/44814
foreach (var tilepath in TilesToFlip)
{
int x = 0;
int y = 0;
var pathToTile = tilepath;
while (pathToTile.Length != 0)
{
var indexToRemove = 1;
if (pathToTile.StartsWith("e"))
{
// e = y: same, x: +1
x++;
}
else if (pathToTile.StartsWith("se"))
{
// se = y: -1, x: +1
y--;
x++;
indexToRemove = 2;
}
else if (pathToTile.StartsWith("sw"))
{
// sw = y: -1, x: same
y--;
indexToRemove = 2;
}
else if (pathToTile.StartsWith("w"))
{
// w = y: same, x: -1
x--;
}
else if (pathToTile.StartsWith("nw"))
{
// nw = y: 1, x: -1
y++;
x--;
indexToRemove = 2;
}
else if (pathToTile.StartsWith("ne"))
{
// ne = y: 1, x: same
y++;
indexToRemove = 2;
}
pathToTile = pathToTile.Substring(indexToRemove);
}
// tile to flip!
var tile = new Tile(x, y);
if (!TilesVisited.ContainsKey(tile.Index))
{
TilesVisited[tile.Index] = tile;
}
var visitedTile = TilesVisited[tile.Index];
visitedTile.Flip();
}
}
public int CountBlackTiles()
{
int sum = TilesVisited.Where((item) => !item.Value.White).Count();
return(sum);
}
