day 6 part 1

AdventOfCode/AdventOfCode.csproj

@@ -4,6 +4,7 @@
     <TargetFramework>net9.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <OutputType>Exe</OutputType>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

AdventOfCode/Day06.cs

@@ -0,0 +1,110 @@
+namespace AdventOfCode;
+
+internal class Day06 : BaseDay
+{
+    private char[][] _map;
+
+    public Day06()
+    {
+        _map = File.ReadAllLines(InputFilePath).Select(x => x.ToCharArray()).ToArray();
+    }
+
+    public override ValueTask<string> Solve_1()
+    {
+        HashSet<Point> visitedLocations = new HashSet<Point>();
+        Point currentGuardPoint = GetGuard();
+        Direction currentGuardDirection = Direction.Up;
+        visitedLocations.Add(currentGuardPoint);
+
+        while (true)
+        {
+            try
+            {
+                (currentGuardPoint, currentGuardDirection) = GetNextMove(currentGuardPoint, currentGuardDirection);
+                visitedLocations.Add(currentGuardPoint);
+            }
+            catch (IndexOutOfRangeException)
+            {
+                break;
+            }
+        }
+
+
+        return new(visitedLocations.Count.ToString());
+    }
+
+    public override ValueTask<string> Solve_2()
+    {
+        return new("");
+    }
+
+    private Point GetGuard()
+    {
+        for (int i = 0; i < _map.Length; ++i)
+        {
+            for (int j = 0; j < _map[0].Length; ++j)
+            {
+                if (_map[i][j] == '^')
+                { 
+                    return new Point(i, j);
+                }
+            }
+        }
+        throw new Exception("Guard not found.");
+    }
+
+    private (Point point, Direction direction) GetNextMove(Point point, Direction direction)
+    {
+        switch (direction)
+        { 
+            case Direction.Up:
+                if (_map[point.I - 1][point.J] == '#')
+                {
+                    return (new Point(point.I, point.J + 1), Direction.Right);
+                }
+                else
+                {
+                    return (new Point(point.I - 1, point.J), Direction.Up);
+                }
+            case Direction.Right:
+                if (_map[point.I][point.J + 1] == '#')
+                {
+                    return (new Point(point.I + 1, point.J), Direction.Down);
+                }
+                else
+                {
+                    return (new Point(point.I, point.J + 1), Direction.Right);
+                }
+            case Direction.Down:
+                if (_map[point.I + 1][point.J] == '#')
+                {
+                    return (new Point(point.I, point.J - 1), Direction.Left);
+                }
+                else
+                {
+                    return (new Point(point.I + 1, point.J), Direction.Down);
+                }
+            case Direction.Left:
+                if (_map[point.I][point.J - 1] == '#')
+                {
+                    return (new Point(point.I - 1, point.J), Direction.Up);
+                }
+                else
+                {
+                    return (new Point(point.I, point.J - 1), Direction.Left);
+                }
+        }
+
+        throw new NotImplementedException();
+    }
+
+    private record Point(int I, int J);
+
+    private enum Direction
+    { 
+        Up,
+        Right,
+        Down,
+        Left
+    }
+}