int Iterate(string input, int iterations)
{
var mtx = Mtx.FromString(".#./..#/###");
var ruleset = new RuleSet(input);
for (var i = 0; i < iterations; i++)
{
mtx = ruleset.Apply(mtx);
}
return(mtx.Count());
}
public static Mtx FromString(string st)
{
st = st.Replace("/", "");
var size = (int)Math.Sqrt(st.Length);
var res = new Mtx(size);
for (int i = 0; i < st.Length; i++)
{
res[i / size, i % size] = st[i] == '#';
}
return(res);
}
IEnumerable <Mtx> Variations(Mtx mtx)
{
for (int j = 0; j < 2; j++)
{
for (int i = 0; i < 4; i++)
{
yield return(mtx);
mtx = mtx.Rotate();
}
mtx = mtx.Flip();
}
}
public Mtx Rotate()
{
var res = new Mtx(this.Size);
for (int i = 0; i < Size; i++)
{
for (int j = 0; j < Size; j++)
{
res[i, j] = this[j, Size - i - 1];
}
}
return(res);
}
public Mtx Flip()
{
var res = new Mtx(this.Size);
for (int irow = 0; irow < Size; irow++)
{
for (int icol = 0; icol < Size; icol++)
{
res[irow, Size - icol - 1] = this[irow, icol];
}
}
return(res);
}
public RuleSet(string input)
{
rules2 = new Dictionary <int, Mtx>();
rules3 = new Dictionary <int, Mtx>();
foreach (var line in input.Split('\n'))
{
var parts = Regex.Split(line, " => ");
var left = parts[0];
var right = parts[1];
var rules =
left.Length == 5 ? rules2 :
left.Length == 11 ? rules3 :
throw new Exception();
foreach (var mtx in Variations(Mtx.FromString(left)))
{
rules[mtx.CodeNumber] = Mtx.FromString(right);
}
}
}
public static Mtx Join(Mtx[] rgmtx)
{
var mtxPerRow = (int)Math.Sqrt(rgmtx.Length);
var res = new Mtx(mtxPerRow * rgmtx[0].Size);
for (int imtx = 0; imtx < rgmtx.Length; imtx++)
{
var mtx = rgmtx[imtx];
for (int irow = 0; irow < mtx.Size; irow++)
{
for (int icol = 0; icol < mtx.Size; icol++)
{
var irowRes = (imtx / mtxPerRow) * mtx.Size + irow;
var icolRes = (imtx % mtxPerRow) * mtx.Size + icol;
res[irowRes, icolRes] = mtx[irow, icol];
}
}
}
return(res);
}
public IEnumerable <Mtx> Split()
{
var blockSize =
Size % 2 == 0 ? 2 :
Size % 3 == 0 ? 3 :
throw new Exception();
for (int irow = 0; irow < Size; irow += blockSize)
{
for (int icol = 0; icol < Size; icol += blockSize)
{
var mtx = new Mtx(blockSize);
for (int drow = 0; drow < blockSize; drow++)
{
for (int dcol = 0; dcol < blockSize; dcol++)
{
mtx[drow, dcol] = this[irow + drow, icol + dcol];
}
}
yield return(mtx);
}
}
}