AdventOfCode/AdventOfCode.Solutions/2022/Day 08/Day08Part2.cs

namespace AdventOfCode.Solutions._2022
{
    public class Day08Part2 : Answerable
    {
        public override int Year { get; set; } = 2022;
        public override int Day { get; set; } = 8;
        public override int Part { get; set; } = 2;

        public override string GetAnswer(byte[] data)
        {
            string[] treeGrid = GetAsStringArray(data);

            int highestScenicScore = 0;
            for (int row = 0; row < treeGrid.Length; row++)
            {
                for (int col = 0; col < treeGrid[row].Length; col++)
                {
                    if (row == 0 || col == 0 || row == treeGrid.Length - 1 || col == treeGrid[row].Length - 1)
                    {
                        // skip the edges
                        continue;
                    }

                    // get the height of the current tree
                    char treeHeight = treeGrid[row][col];

                    List<char> leftTrees = treeGrid[row].Take(col).ToList();
                    int firstLeftBlockingTreeIdx = leftTrees.FindLastIndex(height => height >= treeHeight);
                    int viewCountFromLeft = firstLeftBlockingTreeIdx == -1 ? leftTrees.Count : col - firstLeftBlockingTreeIdx;

                    List<char> rightTrees = treeGrid[row].Skip(col + 1).Take(treeGrid[row].Length - col - 1).Reverse().ToList();
                    int firstRightBlockingTreeIdx = rightTrees.FindLastIndex(height => height >= treeHeight);
                    int viewCountFromRight = firstRightBlockingTreeIdx == -1 ? rightTrees.Count : treeGrid[row].Length - col - firstRightBlockingTreeIdx - 1;

                    List<char> topTrees = treeGrid.Skip(0).Take(row).Select(ints => ints[col]).ToList();
                    int firstTopBlockingTreeIdx = topTrees.FindLastIndex(height => height >= treeHeight);
                    int viewCountFromTop = firstTopBlockingTreeIdx == -1 ? topTrees.Count : row - firstTopBlockingTreeIdx;

                    List<char> bottomTrees = treeGrid.Skip(row + 1).Take(treeGrid.Length - row - 1).Select(ints => ints[col]).Reverse().ToList();
                    int firstBottomBlockingTreeIdx = bottomTrees.FindLastIndex(height => height >= treeHeight);
                    int viewCountFromBottom = firstBottomBlockingTreeIdx == -1 ? bottomTrees.Count : treeGrid.Length - row - firstBottomBlockingTreeIdx - 1;

                    int scenicScore = viewCountFromLeft * viewCountFromRight * viewCountFromTop * viewCountFromBottom;
                    if (scenicScore > highestScenicScore)
                    {
                        highestScenicScore = scenicScore;
                    }
                }
            }

            return highestScenicScore.ToString();
        }
    }
}