From f8b6784df3d421da5ba6580dd065fc6ae24777e0 Mon Sep 17 00:00:00 2001
From: TiagoRG <tiago.rgarcia@ua.pt>
Date: Thu, 8 Jun 2023 21:09:21 +0100
Subject: [PATCH] [2022] Day9 part1 added

---
 Year2022/Day9.cs       | 87 ++++++++++++++++++++++++++++++++++++++++++
 Year2022/Loader2022.cs |  1 +
 2 files changed, 88 insertions(+)
 create mode 100644 Year2022/Day9.cs

diff --git a/Year2022/Day9.cs b/Year2022/Day9.cs
new file mode 100644
index 0000000..b9794f5
--- /dev/null
+++ b/Year2022/Day9.cs
@@ -0,0 +1,87 @@
+namespace AdventOfCode.Year2022;
+
+public class Day9
+{
+    private static readonly List<(char, int)> Moves = new();
+    private static readonly Dictionary<char, List<int>> Position = new()
+    {
+        ['H'] = new List<int>(),
+        ['T'] = new List<int>()
+    };
+    
+    public Day9()
+    {
+        Console.WriteLine("Day9 Solution");
+        File.ReadAllLines("inputs/day9.txt").ToList().ForEach(line =>
+        {
+            string[] split = line.Split(" ");
+            Moves.Add((Convert.ToChar(split[0]), Convert.ToInt32(split[1])));
+        });
+        Console.WriteLine($"Part1 Result: {Part1()}");
+        Console.WriteLine($"Part2 Result: {Part2()}");
+        Console.WriteLine("\n=============================\n");
+    }
+
+    private static int Part1()
+    {
+        Position['H'] = new[] {0, 0}.ToList();
+        Position['T'] = new[] {0, 0}.ToList();
+        HashSet<(int, int)> usedPositions = new HashSet<(int, int)>();
+
+        foreach ((char, int) move in Moves)
+        {
+            List<int> head = Position['H'];
+            List<int> tail = Position['T'];
+            for (int i = 0; i < move.Item2; i++)
+            {
+                if (move.Item1 == 'U')
+                {
+                    head[1]++;
+                    if (ValidatePosition()) continue;
+                    tail[1]++;
+                    tail[0] += head[0] - tail[0];
+                }
+                else if (move.Item1 == 'D')
+                {
+                    head[1]--;
+                    if (ValidatePosition()) continue;
+                    tail[1]--;
+                    tail[0] += head[0] - tail[0];
+                }
+                else if (move.Item1 == 'R')
+                {
+                    head[0]++;
+                    if (ValidatePosition()) continue;
+                    tail[0]++;
+                    tail[1] += head[1] - tail[1];
+                }
+                else if (move.Item1 == 'L')
+                {
+                    head[0]--;
+                    if (ValidatePosition()) continue;
+                    tail[0]--;
+                    tail[1] += head[1] - tail[1];
+                }
+                usedPositions.Add((tail[0], tail[1]));
+            }
+        }
+        return usedPositions.Count;
+    }
+
+    private static int Part2()
+    {
+        Position['H'] = new[] {0, 0}.ToList();
+        Position['T'] = new[] {0, 0}.ToList();
+        HashSet<(int, int)> usedPositions = new HashSet<(int, int)>();
+
+        foreach ((char, int) move in Moves)
+        {
+            
+        }
+        
+        return usedPositions.Count;
+    }
+
+    private static bool ValidatePosition()
+        => Position['H'][0] - Position['T'][0] is > -2 and < 2 && Position['H'][1] - Position['T'][1] is > -2 and < 2;
+}
\ No newline at end of file
diff --git a/Year2022/Loader2022.cs b/Year2022/Loader2022.cs
index 3102c1f..861aefb 100644
--- a/Year2022/Loader2022.cs
+++ b/Year2022/Loader2022.cs
@@ -12,5 +12,6 @@ public static class Loader2022
         new Day6();
         new Day7();
         // new Day8();  -- Commented because it's a slow solution
+        new Day9();
     }
 }
\ No newline at end of file