feat: solved day 10 part 1 and part 2

10/HoofIt/TopoMap.cs

@@ -0,0 +1,119 @@
+namespace HoofIt;
+
+class TopoMap
+{
+  private static readonly Direction[] Directions = [
+    Direction.Up,
+    Direction.Down,
+    Direction.Left,
+    Direction.Right,
+  ];
+  
+  private readonly string[] _grid;
+
+  private TopoMap(string[] input)
+  {
+    _grid = input;
+  }
+
+  public static TopoMap From(string[] input) => new(input);
+
+  public List<int> GetTrailheadRatings()
+  {
+    var ratings = new List<int>();
+    
+    WalkMap((x, y) =>
+    {
+      var hasHeight = int.TryParse(_grid[y][x].ToString(), out var currentHeight);
+
+      if (hasHeight is false || currentHeight is not 0)
+      {
+        return;
+      }
+
+      var rating = GetPathsForTrail(new(x, y, currentHeight));
+      ratings.Add(rating);
+    });
+
+    return ratings;
+  }
+  
+  public List<int> GetTrailheadScores()
+  {
+    var trailScores = new List<int>();
+    
+    WalkMap((x, y) =>
+    {
+      var hasHeight = int.TryParse(_grid[y][x].ToString(), out var currentHeight);
+
+      if (hasHeight is false || currentHeight is not 0)
+      {
+        return;
+      }
+
+      var score = GetPathsForTrail(new(x, y, currentHeight), needToBeUnique: true);
+      trailScores.Add(score);
+    });
+
+    return trailScores;
+  }
+
+  private int GetPathsForTrail(Position trailhead, bool needToBeUnique = false)
+  {
+    var trailheadScore = 0;
+    var visitedPositions = new HashSet<Position>();
+    var positionsToVisit = new Queue<Position>();
+    
+    positionsToVisit.Enqueue(trailhead);
+
+    while (positionsToVisit.Count is not 0)
+    {
+      var currentPosition = positionsToVisit.Dequeue();
+      
+      if (needToBeUnique && visitedPositions.Contains(currentPosition))
+      {
+        continue;
+      }
+
+      visitedPositions.Add(currentPosition);
+      
+      if (currentPosition.Height is 9)
+      {
+        trailheadScore++;
+        continue;
+      }
+
+      foreach (var direction in Directions)
+      {
+        if (currentPosition.TryGetNextPosition(direction, _grid, out var newPosition) is false)
+        {
+          continue;
+        }
+        
+        var heightDifference = newPosition.Height - currentPosition.Height;
+
+        if (heightDifference is not 1)
+        {
+          continue;
+        }
+        
+        positionsToVisit.Enqueue(newPosition);
+      }
+    }
+    
+    return trailheadScore;
+  }
+  
+  private void WalkMap(Action<int, int> callback)
+  {
+    for (var y = 0; y < _grid.Length; y++)
+    {
+      var row = _grid[y];
+
+      for (var x = 0; x < row.Length; x++)
+      {
+        callback(x, y);
+      }
+    }
+  }
+}