Add day 21

Days/Day21.cs

@@ -0,0 +1,183 @@
+using System.Collections.Frozen;
+using System.Numerics;
+using System.Runtime.Intrinsics.X86;
+using System.Text;
+using Spectre.Console;
+
+namespace AdventOfCode.Days;
+
+public class Day21 : Day
+{
+    public override int Number => 21;
+    public override string Name => "Keypad Conundrum";
+
+    private const char Up = '^';
+    private const char Right = '>';
+    private const char Down = 'v';
+    private const char Left = '<';
+    private const char Enter = 'A';
+
+    private readonly Dictionary<char, Point> _numpadPositions = new()
+    {
+        { '7', (0, 0) },
+        { '8', (1, 0) },
+        { '9', (2, 0) },
+        { '4', (0, 1) },
+        { '5', (1, 1) },
+        { '6', (2, 1) },
+        { '1', (0, 2) },
+        { '2', (1, 2) },
+        { '3', (2, 2) },
+        { '0', (1, 3) },
+        { Enter, (2, 3) }
+    };
+
+    private readonly Dictionary<char, Point> _keypadPositions = new()
+    {
+        { Up, (1, 0) },
+        { Enter, (2, 0) },
+        { Left, (0, 1) },
+        { Down, (1, 1) },
+        { Right, (2, 1) }
+    };
+
+    public override void RunPart1(bool display = true)
+    {
+        var codes = ParseCodes();
+        var complexitiesSum = 0;
+
+        foreach (var code in codes)
+        {
+            // Get first keypad sequence
+            var firstKeypadSequence = new StringBuilder();
+            var currentInput = Enter;
+
+            foreach (var digit in code)
+            {
+                firstKeypadSequence.Append(GetNumpadMoveSequence(currentInput, digit));
+
+                currentInput = digit;
+            }
+
+            // Get second keypad sequence
+            var secondKeypadSequence = new StringBuilder();
+            currentInput = Enter;
+
+            foreach (var input in firstKeypadSequence.ToString())
+            {
+                secondKeypadSequence.Append(GetKeypadMoveSequence(currentInput, input));
+
+                currentInput = input;
+            }
+
+            // Get third and last keypad sequence
+            var thirdKeypadSequence = new StringBuilder();
+            currentInput = Enter;
+
+            foreach (var input in secondKeypadSequence.ToString())
+            {
+                thirdKeypadSequence.Append(GetKeypadMoveSequence(currentInput, input));
+
+                currentInput = input;
+            }
+
+            complexitiesSum += thirdKeypadSequence.Length * int.Parse(code.AsSpan()[..^1]);
+        }
+
+        if (display)
+        {
+            AnsiConsole.MarkupLine($"[green]Sum of complexities: [yellow]{complexitiesSum}[/][/]");
+        }
+    }
+
+    public override void RunPart2(bool display = true)
+    {
+
+    }
+
+    private string GetNumpadMoveSequence(char origin, char destination)
+    {
+        var originPosition = _numpadPositions[origin];
+        var destinationPosition = _numpadPositions[destination];
+
+        var move = destinationPosition - originPosition;
+
+        var moveRight = move.X > 0;
+        var moveDown = move.Y > 0;
+
+        var sequence = string.Concat(
+            new string(moveRight ? Right : Left, Math.Abs(move.X)),
+            new string(moveDown ? Down : Up, Math.Abs(move.Y)),
+            Enter.ToString() // Always end on Enter to press key
+        );
+
+        return sequence;
+    }
+
+    private string GetKeypadMoveSequence(char origin, char destination)
+    {
+        var originPosition = _keypadPositions[origin];
+        var destinationPosition = _keypadPositions[destination];
+
+        var move = destinationPosition - originPosition;
+
+        var moveRight = move.X > 0;
+        var moveDown = move.Y > 0;
+
+        var sequence = string.Concat(
+            new string(moveDown ? Down : Up, Math.Abs(move.Y)),
+            new string(moveRight ? Right : Left, Math.Abs(move.X)),
+            Enter.ToString() // Always end on Enter to press key
+        );
+
+        return sequence;
+    }
+
+    private List<string> ParseCodes()
+    {
+        var codes = new List<string>();
+
+        foreach (var line in Input.AsSpan().EnumerateLines())
+        {
+            codes.Add(line.ToString());
+        }
+
+        return codes;
+    }
+
+    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);
+
+        public int DistanceTo(Point other)
+        {
+            var distance = other - this;
+
+            return Math.Abs(distance.X) + Math.Abs(distance.Y);
+        }
+    }
+}

Inputs/Day21.txt

@@ -0,0 +1,5 @@
+029A
+980A
+179A
+456A
+379A