private static uint BioDiversity(CharMap map)
{
var(min, max) = map.MinMax();
var width = max.Y - min.Y + 1;
uint val = 0;
foreach (var pos in map.AllPoints(c => c == '#'))
{
var position = pos.Y * width + pos.X;
val += 1U << position;
}
return(val);
}
private static string[] CalculatePath(CharMap map)
{
var pos = map.AllPoints(ch => "^v<>".Contains(ch)).First();
var vc = map[pos];
var direction =
vc == '^' ? Direction.Up :
vc == '>' ? Direction.Right :
vc == 'v' ? Direction.Down :
vc == '<' ? Direction.Left : 0; // 0 can't happen
var path = new List <string>();
var stretch = 0;
while (true)
{
var originalDirection = direction;
if (map[pos.Move(direction)] == '#')
{
pos = pos.Move(direction);
stretch++;
continue;
}
if (stretch > 0)
{
path.Add(stretch.ToString());
stretch = 0;
}
if (map[pos.Move(direction.TurnLeft())] == '#')
{
direction = direction.TurnLeft();
path.Add("L");
}
else if (map[pos.Move(direction.TurnRight())] == '#')
{
direction = direction.TurnRight();
path.Add("R");
}
else
{
return(path.ToArray());
}
//Console.WriteLine(path);
}
}
protected override int Part1(string[] input)
{
var map = new CharMap();
var lines = input;
for (var y = 0; y < lines.Length; y++)
{
var line = lines[y];
for (var x = 0; x < line.Length; x++)
{
map[x][y] = line[x];
}
}
var seen = new HashSet <uint>();
while (true)
{
//map.ConsoleWrite(false);
////Console.ReadKey();
var bio = BioDiversity(map);
if (seen.Contains(bio))
{
return((int)bio);
}
seen.Add(bio);
var nextmap = new CharMap();
foreach (var pos in map.AllPoints().ToArray()) // ToArray should not be needed?
{
var n = pos.LookAround().Count(p => map[p] == '#');
nextmap[pos] = map[pos] == '#'
? n == 1 ? '#' : '.'
: n == 1 || n == 2 ? '#' : '.';
}
map = nextmap;
}
throw new Exception("No result found");
}