feat: solved day 12 part 2 🥳

12/GardenGroups/Garden.cs

@@ -0,0 +1,112 @@
+namespace GardenGroups;
+
+class Garden
+{
+  private static readonly Direction[] Directions = [
+    Direction.Up,
+    Direction.Down,
+    Direction.Left,
+    Direction.Right,
+  ];
+  
+  private readonly string[] _grid;
+
+  private Garden(string[] grid)
+  {
+    _grid = grid;
+  }
+
+  public static Garden From(string[] input) => new(input);
+  
+  public int CalculateFencePriceBasedOnSides()
+  {
+    var visitedPositions = new HashSet<Position>();
+    var total = 0;
+    
+    WalkGarden((x, y) =>
+    {
+      var currentPosition = new Position(x, y, _grid[y][x]);
+
+      if (visitedPositions.Contains(currentPosition))
+      {
+        return;
+      }
+      
+      var region = FindRegion(currentPosition, visitedPositions);
+      total += region.CalculateFencePriceBasedOnSides();
+    });
+
+    return total;
+  }
+  
+  public int CalculateFencePriceBasedOnPerimeter()
+  {
+    var visitedPositions = new HashSet<Position>();
+    var total = 0;
+    
+    WalkGarden((x, y) =>
+    {
+      var currentPosition = new Position(x, y, _grid[y][x]);
+
+      if (visitedPositions.Contains(currentPosition))
+      {
+        return;
+      }
+      
+      var region = FindRegion(currentPosition, visitedPositions);
+      total += region.CalculateFencePriceBasedOnPerimeter();
+    });
+
+    return total;
+  }
+
+  private Region FindRegion(Position position, HashSet<Position> visitedPositions)
+  {
+    var region = Region.From(position);
+    var positionsToVisit = new Queue<Position>();
+    
+    positionsToVisit.Enqueue(position);
+
+    while (positionsToVisit.Count is not 0)
+    {
+      var currentPosition = positionsToVisit.Dequeue();
+      
+      if (visitedPositions.Contains(currentPosition))
+      {
+        continue;
+      }
+      
+      region.AddPosition(currentPosition);
+      visitedPositions.Add(currentPosition);
+
+      foreach (var direction in Directions)
+      {
+        if (
+          currentPosition.TryGetNextPosition(direction, _grid, out var newPosition) is false ||
+          newPosition.PlantType != currentPosition.PlantType
+        )
+        {
+          region.IncreasePerimeter();
+          continue;
+        }
+        
+        positionsToVisit.Enqueue(newPosition);
+      }
+    }
+    
+    return region;
+  }
+  
+  private void WalkGarden(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);
+      }
+    }
+  }
+}