2024-01,02

2024/Day01.cs

@@ -1,10 +1,34 @@
 namespace _2024;
 
-public class Day01 : ISolution
-{
-    public void Run()
-    {
-        var _ = File.ReadAllText("input/01");
-        Console.WriteLine("The solution for day 01 is not implmented yet");
+public class Day01 : ISolution {
+    public void Run() {
+        // Read all lines from the input file
+        var lines = File.ReadAllLines("input/01");
+
+        // Two lists to hold the first and second integers per line
+        var left = new List<int>();
+        var right = new List<int>();
+
+        foreach (var line in lines) {
+            if (string.IsNullOrWhiteSpace(line)) continue;
+
+            var parts = line.Split(' ', StringSplitOptions.RemoveEmptyEntries);
+            if (parts.Length < 2) {
+                Console.WriteLine("Bad parse");
+                return;
+            }
+
+            if (int.TryParse(parts[0], out var a) && int.TryParse(parts[1], out var b)) {
+                left.Add(a);
+                right.Add(b);
+            }
+        }
+        
+        var leftSorted = left.OrderBy(x => x).ToList();
+        var rightSorted = right.OrderBy(x => x).ToList();
+        Console.WriteLine(leftSorted.Select((t, i) => Math.Abs(t - rightSorted[i])).Sum());
+
+        Console.WriteLine(left.Sum(i => right.Count(x => x == i) * i));
     }
 }
+    

2024/Day02.cs

@@ -4,7 +4,21 @@ public class Day02 : ISolution
 {
     public void Run()
     {
-        var _ = File.ReadAllText("input/02");
-        Console.WriteLine("The solution for day 02 is not implmented yet");
+        var input = File.ReadAllText("input/02")
+            .Split('\n')
+            .Select(line => line.Split(' ')
+                .Select(int.Parse)
+                .ToList())
+            .ToList();
+
+        Console.WriteLine(PartOne(input));
+    }
+    
+    private static int PartOne(List<List<int>> list) {
+        return list.Select(line => Enumerable.Range(1, Math.Max(0, line.Count - 1))
+                .Select(i => line[i] - line[i - 1])
+                .ToList())
+            .Where(diffs => diffs.All(d => d > 0) || diffs.All(d => d < 0))
+            .Count(diffs => !diffs.Any(d => Math.Abs(d) is < 1 or > 3));
     }
 }

README.md

@@ -3,13 +3,23 @@
 Advent Of Code solutions using a different language each year
 
 2015: C99
+
 2016: Go
+
 2017: TBD
+
 2018: TBD
+
 2019: TBD
+
 2020: TBD
+
 2021: TBD
+
 2022: TBD
+
 2023: TBD
+
 2024: C#
+
 2025: TBD