119 lines
4.1 KiB
C#
119 lines
4.1 KiB
C#
namespace AdventOfCodeLibrary._2022.Day_08
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{
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internal struct Tree
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{
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internal int X;
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internal int Y;
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internal char Height;
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internal bool IsVisible;
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internal Tree(int x, int y, char height)
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{
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X = x;
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Y = y;
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Height = height;
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IsVisible = false;
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}
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}
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internal class TreeChecker
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{
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private Tree[][] treeGrid;
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private Tree[][] rotatedGrid;
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internal int VisibleTrees(string[] treeArray)
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{
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treeGrid = new Tree[treeArray.Length][];
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rotatedGrid = new Tree[treeArray[0].Length][];
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for (int verticalIndex = 0; verticalIndex < treeArray.Length; verticalIndex++)
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{
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bool firstVertial = true;
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for (int horizontalIndex = 0; horizontalIndex < treeArray[0].Length; horizontalIndex++)
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{
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if (firstVertial)
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{
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treeGrid[verticalIndex] = new Tree[treeArray[0].Length];
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firstVertial = false;
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}
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if (verticalIndex == 0)
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{
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rotatedGrid[horizontalIndex] = new Tree[treeArray.Length];
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}
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Tree tree = new Tree(verticalIndex, horizontalIndex, treeArray[verticalIndex][horizontalIndex]);
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//Console.WriteLine($"Adding Tree to [{verticalIndex}][{horizontalIndex}] and [{horizontalIndex}][{verticalIndex}]");
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treeGrid[verticalIndex][horizontalIndex] = tree;
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rotatedGrid[horizontalIndex][verticalIndex] = tree;
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}
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}
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int visible = 0;
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// start from the top
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Tree[] currentHighest = treeGrid[0];
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// from top to bottom
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for (int treeIndex = 1; treeIndex < treeArray.Length - 2; treeIndex++)
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{
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int tmp = CheckVisibleTrees(ref currentHighest, treeGrid[treeIndex]);
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visible += tmp;
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}
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currentHighest = treeGrid[^1];
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// from bottom to top
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for (int treeIndex = treeArray.Length - 1; treeIndex > 1 ; treeIndex--)
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{
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int tmp = CheckVisibleTrees(ref currentHighest, treeGrid[treeIndex]);
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visible += tmp;
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}
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currentHighest = rotatedGrid[0];
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// from top to bottom with the rotated array
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for (int treeIndex = rotatedGrid.Length - 1; treeIndex > 1; treeIndex--)
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{
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int tmp = CheckVisibleTrees(ref currentHighest, rotatedGrid[treeIndex]);
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visible += tmp;
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}
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currentHighest = rotatedGrid[^1];
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// from bottom to top with the rotated array
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for (int treeIndex = rotatedGrid.Length - 1; treeIndex > 1; treeIndex--)
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{
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int tmp = CheckVisibleTrees(ref currentHighest, rotatedGrid[treeIndex]);
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visible += tmp;
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}
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// add the outside trees
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int edgeTrees = (2 * treeGrid.Length) + (2 * (treeGrid[0].Length - 2));
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// return the result
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return visible + edgeTrees;
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}
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private int CheckVisibleTrees(ref Tree[] currentHighest, Tree[] treeLineToCheck)
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{
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int visible = 0;
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for (int treeIndex = 1; treeIndex < treeLineToCheck.Length - 1; treeIndex++)
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{
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Tree toCheck = treeLineToCheck[treeIndex];
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int diff = toCheck.Height - currentHighest[treeIndex].Height;
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if (diff > 0 && !treeGrid[toCheck.X][toCheck.Y].IsVisible)
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{
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visible++;
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treeGrid[toCheck.X][toCheck.Y].IsVisible = true;
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currentHighest[treeIndex] = treeLineToCheck[treeIndex];
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}
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}
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return visible;
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}
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}
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}
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