10-2023 Part 2

laurent-seguin · laurent-seguin · commit db6872b296cd · 2023-12-12T21:45:01.000+01:00
diff --git a/2023/Day10/Solution.cs b/2023/Day10/Solution.cs
@@ -15,12 +15,12 @@ public object PartOne(string input)
         // We find where the 'S' is
         var startingPoint = FindStartingPoint(lines);
         pipesMap.Add(startingPoint.Key, startingPoint.Value);
-        
+
         while (true)
         {
             var currentPoint = new ValueTuple<int, int>();
             var newDirection = Direction.Down;
-        
+
             if (pipesMap.Last().Value == Direction.Right)
             {
                 currentPoint = (pipesMap.Last().Key.Item1, pipesMap.Last().Key.Item2 + 1);
@@ -41,22 +41,104 @@ public object PartOne(string input)
                 currentPoint = (pipesMap.Last().Key.Item1 + 1, pipesMap.Last().Key.Item2);
                 newDirection = GetNewDirection(Direction.Down, lines[currentPoint.Item1][currentPoint.Item2]);
             }
-        
+
             if (newDirection == Direction.End)
             {
                 // We went back to the previous point
                 break;
             }
-            
+
             pipesMap.Add(currentPoint, newDirection);
         }
-        
+
         return (pipesMap.Count) / 2;
     }
 
     public object PartTwo(string input)
     {
-        return 0;
+        var lines = ParseLines(input);
+        var pipesMap = new Dictionary<(int, int), Direction>();
+        var visitedTiles = new HashSet<(int, int)>();
+        // We find where the 'S' is
+        var startingPoint = FindStartingPoint(lines);
+
+        pipesMap.Add(startingPoint.Key, startingPoint.Value);
+        visitedTiles.Add(startingPoint.Key);
+
+        while (true)
+        {
+            var currentPoint = new ValueTuple<int, int>();
+            var newDirection = Direction.Down;
+
+            if (pipesMap.Last().Value == Direction.Right)
+            {
+                currentPoint = (pipesMap.Last().Key.Item1, pipesMap.Last().Key.Item2 + 1);
+                newDirection = GetNewDirection(Direction.Right, lines[currentPoint.Item1][currentPoint.Item2]);
+            }
+            else if (pipesMap.Last().Value == Direction.Left)
+            {
+                currentPoint = (pipesMap.Last().Key.Item1, pipesMap.Last().Key.Item2 - 1);
+                newDirection = GetNewDirection(Direction.Left, lines[currentPoint.Item1][currentPoint.Item2]);
+            }
+            else if (pipesMap.Last().Value == Direction.Up)
+            {
+                currentPoint = (pipesMap.Last().Key.Item1 - 1, pipesMap.Last().Key.Item2);
+                newDirection = GetNewDirection(Direction.Up, lines[currentPoint.Item1][currentPoint.Item2]);
+            }
+            else if (pipesMap.Last().Value == Direction.Down)
+            {
+                currentPoint = (pipesMap.Last().Key.Item1 + 1, pipesMap.Last().Key.Item2);
+                newDirection = GetNewDirection(Direction.Down, lines[currentPoint.Item1][currentPoint.Item2]);
+            }
+
+            if (newDirection == Direction.End)
+            {
+                // We went back to the previous point
+                break;
+            }
+
+            pipesMap.Add(currentPoint, newDirection);
+            visitedTiles.Add(currentPoint);
+        }
+
+        // We modify Starting point for algo
+        var index = startingPoint.Key.Item2;
+        var str = lines[startingPoint.Key.Item1];
+        var newStr = str.Remove(index, 1).Insert(index, "L");
+        lines[startingPoint.Key.Item1] = newStr;
+
+        var insideCount = 0;
+        for (int y = 1; y < lines.Length - 1; y++)
+        {
+            for (int x = 1; x < lines[0].Length - 1; x++)
+            {
+                if (visitedTiles.Contains((y, x)))
+                {
+                    continue;
+                }
+
+                var crossings = 0;
+
+                for (int i = x + 1; i < lines[0].Length; i++)
+                {
+                    var tile = lines[y][i];
+                    // If we find a wall
+                    var symbols = new[] { '|', 'J', 'L' };
+
+                    if (visitedTiles.Contains((y, i)) && symbols.Contains(tile))
+                    {
+                        crossings++;
+                    }
+                }
+
+                if (crossings % 2 == 1)
+                {
+                    insideCount++;
+                }
+            }
+        }
+
+        return insideCount;
     }
 
     private static string[] ParseLines(string input) =>
@@ -127,4 +209,4 @@ internal enum Direction
     Left,
     Right,
     End
-}
+}
diff --git a/2023/Day10/input.refout b/2023/Day10/input.refout
@@ -1 +1,2 @@
-6875
+6875
+471
diff --git a/2023/SplashScreen.cs b/2023/SplashScreen.cs
@@ -9,23 +9,26 @@ public void Show() {
 
         var color = Console.ForegroundColor;
         Write(0xcc00, false, "           ▄█▄ ▄▄█ ▄ ▄ ▄▄▄ ▄▄ ▄█▄  ▄▄▄ ▄█  ▄▄ ▄▄▄ ▄▄█ ▄▄▄\n           █▄█ █ █ █ █ █▄█ █ █ █   █ █ █▄ ");
-            Write(0xcc00, false, " █  █ █ █ █ █▄█\n           █ █ █▄█ ▀▄▀ █▄▄ █ █ █▄  █▄█ █   █▄ █▄█ █▄█ █▄▄  0x0000 | 2023\n           ");
-            Write(0xcc00, false, " \n                                                            \n                                     ");
-            Write(0xcc00, false, "                       \n                                                            \n               ");
-            Write(0xcc00, false, "                                             \n                                                      ");
-            Write(0xcc00, false, "      \n           ");
-            Write(0x333333, false, "        *                                          ");
-            Write(0x666666, false, "12\n           ");
-            Write(0x333333, false, "'                       '                        \n           ");
+            Write(0xcc00, false, " █  █ █ █ █ █▄█\n           █ █ █▄█ ▀▄▀ █▄▄ █ █ █▄  █▄█ █   █▄ █▄█ █▄█ █▄▄  /^2023$/\n            \n   ");
+            Write(0xcc00, false, "                                                         \n                                          ");
+            Write(0xcc00, false, "                  \n                                                            \n           ");
+            Write(0x333333, false, "                        *                          ");
+            Write(0x666666, false, "13\n                                                            \n                   *                ");
+            Write(0x666666, false, "                          ");
+            Write(0xcccccc, false, "12 ");
+            Write(0x666666, false, "**\n           ");
+            Write(0xd4dde4, false, "'                       '                        \n           ");
             Write(0x666666, false, "      *                                            ");
             Write(0xcccccc, false, "11 ");
-            Write(0x666666, false, "**\n               '.      *     ..'");
+            Write(0x666666, false, "**\n               ");
+            Write(0xd4dde4, false, "'.      ");
+            Write(0xffff66, true, "*     ");
+            Write(0xd4dde4, false, "..'");
             Write(0xe3b585, false, "' ''...                       ");
             Write(0xcccccc, false, "10 ");
-            Write(0xffff66, false, "*");
-            Write(0x666666, false, "*\n                     ");
+            Write(0xffff66, false, "**\n                     ");
             Write(0xe3b585, false, ".");
-            Write(0x333333, false, "'''");
+            Write(0xd4dde4, false, "'''");
             Write(0xe3b585, false, "~ ~ ~ ~   ");
             Write(0x6b4d3b, false, "### ");
             Write(0xe3b585, false, "''.                  \n                   .' ~  ");
diff --git a/2023/calendar.svg b/2023/calendar.svg
