public void Solve(ReadOnlySpan <byte> input, Solution solution)
{
var grid = new Day24Grid();
PopulateInitialBlackTiles(input, grid);
int part1 = grid.AliveCount;
for (int i = 0; i < 100; i++)
{
grid.Step();
}
int part2 = grid.AliveCount;
solution.SubmitPart1(part1);
solution.SubmitPart2(part2);
}
private static void PopulateInitialBlackTiles(ReadOnlySpan <byte> input, Day24Grid grid)
{
int q = 128;
int r = 128;
int i = 0;
while (i < input.Length)
{
byte c = input[i++];
switch (c)
{
case (byte)'\n':
grid.FlipTile(q, r);
q = 128;
r = 128;
break;
case (byte)'w':
q--;
break;
case (byte)'e':
q++;
break;
case (byte)'n':
r--;
if (input[i++] == 'e')
{
q++;
}
break;
case (byte)'s':
r++;
if (input[i++] == 'w')
{
q--;
}
break;
}
}
}