anth

namespace LightBulbs
{
    public class LightBulbs : ILightBulbs
    {
        public new static ILightBulbs GetInstance()
        {
            return lightBulbsInstance ?? (lightBulbsInstance = new LightBulbs());
        }

        public override int CountLightsOn(bool[,] lightsBoard, int s)
        {
            int rows = lightsBoard.GetLength(0);
            int cols = lightsBoard.GetLength(1);

            for (int i = 0; i < s; ++i)
            {
                var copy = this.Copy(lightsBoard);

                for (int r = 0; r < rows; ++r)
                {
                    for (int c = 0; c < cols; ++c)
                    {
                        if (this.IsCorner(copy, r, c))
                            continue;

                        int turnedOnNeighbors = this.FindTurnedOnNeighbors(copy, r, c);

                        if (copy[r, c])
                        {
                            if (!(turnedOnNeighbors == 2 || turnedOnNeighbors == 3))
                                lightsBoard[r, c] = false;
                        }
                        else
                        {
                            if (turnedOnNeighbors == 3)
                                lightsBoard[r, c] = true;
                        }
                    }
                }
            }

            int count = 0;

            for (int r = 0; r < rows; ++r)
            {
                for (int c = 0; c < cols; ++c)
                {
                    if (lightsBoard[r, c])
                        count++;
                }
            }

            return count;
        }

        private bool[,] Copy(bool[,] from)
        {
            int rows = from.GetLength(0);
            int cols = from.GetLength(1);

            bool[,] copy = new bool[rows, cols];
            for (int r = 0; r < rows; ++r)
                for (int c = 0; c < cols; ++c)
                    copy[r, c] = from[r, c];

            return copy;
        }

        private bool IsCorner(bool[,] lightsBoard, int row, int col)
        {
            int rows = lightsBoard.GetLength(0);
            int cols = lightsBoard.GetLength(1);

            if (row == 0 && col == 0 ||
                row == 0 && col == cols - 1 ||
                row == rows - 1 && col == 0 ||
                row == rows - 1 && col == cols - 1)
            {
                return true;
            }

            return false;
        }

        private int FindTurnedOnNeighbors(bool[,] lightsBoard, int row, int col)
        {
            int count = 0;

            int rows = lightsBoard.GetLength(0);
            int cols = lightsBoard.GetLength(1);


            for (int r = -1; r <= 1; ++r)
            {
                for (int c = -1; c <= 1; ++c)
                {
                    int nRow = row + r;
                    int nCol = col + c;

                    if (nRow == row && nCol == col)
                        continue;

                    if (nRow >= 0 && nCol >= 0 && nRow <= rows - 1 && nCol <= cols - 1)
                    {
                        if (lightsBoard[nRow, nCol])
                            count++;
                    }
                }
            }

            return count;
        }
    }
}