public static int SolvePart1(string input)
{
var squaresUsed = 0;
for (var i = 0; i < 128; i++)
{
var knotHash = Day10.SolvePart2($"{input}-{i}", 256);
var binaryString = String.Join("", knotHash.Select(x => Convert.ToString(Convert.ToInt32(x.ToString(), 16), 2).PadLeft(4, '0')));
squaresUsed += binaryString.Replace("0", "").Length;
}
return(squaresUsed);
}
public static int SolvePart2(string input)
{
var squares = new List <DiskSquare>();
for (var i = 0; i < 128; i++)
{
var knotHash = Day10.SolvePart2($"{input}-{i}", 256);
var binaryString = String.Join("", knotHash.Select(x => Convert.ToString(Convert.ToInt32(x.ToString(), 16), 2).PadLeft(4, '0')));
for (int j = 0; j < binaryString.Length; j++)
{
squares.Add(new DiskSquare {
Point = new Point(j, i), Used = binaryString[j] == '1'
});
}
}
var currentRegionNumber = 0;
foreach (var square in squares)
{
if (square.Used && square.RegionNumber == null)
{
var queue = new Queue <DiskSquare>(new [] { square });
while (queue.Count != 0)
{
var queueSquare = queue.Dequeue();
var neighbours = squares.Where(x =>
x.Used && Day3.CalculateManhattanDistance(queueSquare.Point, x.Point) == 1).ToArray();
var neighbourRegionNumber = neighbours.Where(x => x.RegionNumber.HasValue)
.Select(x => x.RegionNumber).FirstOrDefault();
queueSquare.RegionNumber = neighbourRegionNumber ?? ++currentRegionNumber;
foreach (var neighbour in neighbours.Where(x => !x.RegionNumber.HasValue))
{
queue.Enqueue(neighbour);
}
}
}
}
return(currentRegionNumber);
}