Add day 15

Days/Day15.cs

@@ -0,0 +1,193 @@
+using System.Collections.Frozen;
+using System.Numerics;
+using System.Text;
+using Spectre.Console;
+
+namespace AdventOfCode.Days;
+
+public class Day15 : Day
+{
+    public override int Number => 15;
+    public override string Name => "Warehouse Woes";
+
+    private const int Size = 50;
+
+    private const char Wall = '#';
+    private const char Box = 'O';
+    private const char Empty = '.';
+
+    private const char InstructionLeft = '<';
+    private const char InstructionRight = '>';
+    private const char InstructionUp = '^';
+    private const char InstructionDown = 'v';
+
+    public override void RunPart1(bool display = true)
+    {
+        var (map, position, instructions) = ParseMap();
+
+        foreach (var instruction in instructions)
+        {
+            var direction = instruction switch
+            {
+                InstructionLeft => new Point(-1, 0),
+                InstructionRight => new Point(1, 0),
+                InstructionUp => new Point(0, -1),
+                InstructionDown => new Point(0, 1),
+                _ => throw new ArgumentException($"Invalid instruction: {instruction}")
+            };
+
+            var destination = position + direction;
+
+            // Destination is free, just move
+            if (map[destination.X, destination.Y] is not (Wall or Box))
+            {
+                position = destination;
+            }
+            // Destination is a box, check if there is a free space further up and move accordingly
+            else if (map[destination.X, destination.Y] is Box)
+            {
+                var pushTarget = destination + direction;
+
+                while (map[pushTarget.X, pushTarget.Y] is Box)
+                {
+                    pushTarget += direction;
+                }
+
+                // Cannot move anything since there is a wall
+                if (map[pushTarget.X, pushTarget.Y] is Wall)
+                {
+                    continue;
+                }
+
+                // Move robot and boxes (only need to move first and last box of a chain)
+                position = destination;
+
+                map[destination.X, destination.Y] = Empty;
+                map[pushTarget.X, pushTarget.Y] = Box;
+            }
+            // Else destination is a wall, do nothing
+        }
+
+        var coordinatesSum = 0;
+
+        // Count gps coordinates
+        for (var x = 0; x < Size; x++)
+        {
+            for (var y = 0; y < Size; y++)
+            {
+                if (map[x, y] is Box)
+                {
+                    coordinatesSum += 100 * y + x;
+
+                }
+            }
+        }
+
+        if (display)
+        {
+            AnsiConsole.MarkupLine($"[green]Sum of boxes GPS coordinates: [yellow]{coordinatesSum}[/][/]");
+        }
+    }
+
+    private static void DisplayGrid(char[,] map)
+    {
+        for (var y = 0; y < Size; y++)
+        {
+            for (var x = 0; x < Size; x++)
+            {
+                AnsiConsole.Write(map[x, y]);
+            }
+
+            AnsiConsole.WriteLine();
+        }
+
+        AnsiConsole.WriteLine();
+    }
+
+    public override void RunPart2(bool display = true)
+    {
+
+    }
+
+    private (char[,] Map, Point Start, List<char> Instructions) ParseMap()
+    {
+        var readingMap = true;
+
+        var map = new char[Size, Size];
+
+        Point start = default;
+
+        var instructions = new List<char>();
+
+        var y = 0;
+        foreach (var line in Input.AsSpan().EnumerateLines())
+        {
+            if (line.IsWhiteSpace())
+            {
+                readingMap = false;
+
+                continue;
+            }
+
+            if (readingMap)
+            {
+                var x = 0;
+                foreach (var symbol in line)
+                {
+                    map[x, y] = Empty;
+
+                    if (symbol is Wall or Box)
+                    {
+                        map[x, y] = symbol;
+                    }
+                    else if (symbol is '@')
+                    {
+                        start = new Point(x, y);
+                    }
+
+                    x++;
+                }
+
+                y++;
+            }
+            else
+            {
+                foreach (var instruction in line)
+                {
+                    instructions.Add(instruction);
+                }
+            }
+        }
+
+        return (map, start, instructions);
+    }
+
+    private readonly record struct Point(int X, int Y)
+        : IAdditionOperators<Point, Point, Point>,
+            ISubtractionOperators<Point, Point, Point>,
+            IMultiplyOperators<Point, int, Point>
+    {
+        public static Point operator +(Point left, Point right)
+        {
+            return new Point(left.X + right.X, left.Y + right.Y);
+        }
+
+        public static Point operator -(Point left, Point right)
+        {
+            return new Point(left.X - right.X, left.Y - right.Y);
+        }
+
+        public static Point operator *(Point left, int right)
+        {
+            return new Point(left.X * right, left.Y * right);
+        }
+
+        public static Point operator *(int left, Point right)
+        {
+            return new Point(right.X * left, right.Y * left);
+        }
+
+        public static implicit operator Point((int X, int Y) point)
+            => new(point.X, point.Y);
+    }
+}