Initial Commit

2024/Day05CSharp/Day05CSharp.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\AdventCommon\AdventCommon.csproj" />
+  </ItemGroup>
+
+</Project>

2024/Day05CSharp/Program.cs

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+using System.Runtime.InteropServices;
+
+var exParsed = new Day05Parsed("example-input.txt");
+
+Console.WriteLine("Example Part01: {0}", exParsed.GetPart01());
+Console.WriteLine("Example Part02: {0}", exParsed.GetPart02());
+
+var pzParsed = new Day05Parsed("puzzle-input.txt");
+
+Console.WriteLine("Puzzle Part01: {0}", pzParsed.GetPart01());
+Console.WriteLine("Puzzle Part02: {0}", pzParsed.GetPart02());
+
+class Day05Parsed : AdventCommon.ParsedInput
+{
+    public class Page : IComparable<Page>
+    {
+        public static Dictionary<int, HashSet<int>> RulesByPage = new Dictionary<int, HashSet<int>>();
+
+        public Page(int value) => Value = value;
+
+        public int Value { get; set; }
+
+        public int CompareTo(Page? other)
+        {
+            if (other == null) throw new Exception("Other is null");
+
+            if (this.Value ==  other.Value) return 0;
+
+            if (!RulesByPage.ContainsKey(this.Value))
+            {
+                // If there's no key, then this MUST be at the end so its the "biggest"
+                return 1;
+            }
+
+            if (RulesByPage[this.Value].Contains(other.Value))
+            {
+                return -1;
+            } 
+            else if (RulesByPage[other.Value].Contains(this.Value))
+            {
+                return 1;
+            }
+
+            throw new Exception("Unable to compare!");
+        }
+    }
+    public class OrderingRule
+    {
+        public OrderingRule(string line)
+        {
+            LeftPage = Int32.Parse(line.Split('|')[0]);
+            RightPage = Int32.Parse(line.Split('|')[1]);
+        }
+
+        public int LeftPage { get; set; }
+        public int RightPage { get; set; }
+    }
+
+    public class Update
+    {
+        public Update(string[] pages)
+        {
+            foreach (var page in pages)
+            {
+                Pages.Add(Int32.Parse(page));
+            }
+        }
+
+        public List<int> Pages { get; set; } = new List<int>();
+    }
+
+    public Dictionary<int, HashSet<int>> RulesByPage { get; set; } = new Dictionary<int, HashSet<int>>();
+
+    public List<OrderingRule> Rules { get; set; } = new List<OrderingRule>();
+    public List<Update> Updates { get; set; } = new List<Update>();
+
+    public Day05Parsed(string fileName) : base(fileName)
+    {
+        foreach (var rule in Rules)
+        {
+            if (RulesByPage.ContainsKey(rule.LeftPage))
+            {
+                RulesByPage[rule.LeftPage].Add(rule.RightPage);
+            }
+            else
+            {
+                RulesByPage.Add(rule.LeftPage, new HashSet<int>() { rule.RightPage });
+            }
+        }
+
+        Page.RulesByPage = RulesByPage;
+    }
+
+    public override int GetPart01()
+    {
+        List<Update> validUpdates = new List<Update>();
+        
+        Updates.ForEach(update => {
+            if (IsUpdateValid(update)) validUpdates.Add(update);
+        });
+
+        // We have all the valid updates, now get the "middle" item
+        int middlePageNumberSum = 0;
+
+        foreach (var update in validUpdates)
+        {
+            middlePageNumberSum += update.Pages[update.Pages.Count / 2];
+        }
+
+        return middlePageNumberSum;
+    }
+
+    public override int GetPart02()
+    {
+        List<Update> invalidUpdates = new List<Update>();
+
+        Updates.ForEach(update => {
+            if (!IsUpdateValid(update)) invalidUpdates.Add(update);
+        });
+
+
+        int middleSum = 0;
+
+        foreach (var update in invalidUpdates)
+        {
+            List<Page> pages = new List<Page>();
+
+            foreach (var page in update.Pages)
+            {
+                pages.Add(new Page(page));
+            }
+
+            pages.Sort();
+
+            middleSum += pages[pages.Count / 2].Value;
+        }        
+
+        return middleSum;
+    }
+
+
+    private bool IsUpdateValid(Update update)
+    {
+        bool isUpdateValid = true;
+
+        for (int pageIndex = 0; pageIndex < update.Pages.Count; pageIndex++)
+        {
+            if (!RulesByPage.ContainsKey(update.Pages[pageIndex]))
+            {
+                continue;
+            }
+
+            var rules = RulesByPage[update.Pages[pageIndex]];
+
+            // Make sure current page has rules that say its before all the subsequent pages
+            for (int subIndex = pageIndex + 1; subIndex < update.Pages.Count; subIndex++)
+            {
+                if (!rules.Contains(update.Pages[subIndex]))
+                {
+                    isUpdateValid = false;
+                    break;
+                }
+            }
+
+            // Go backwards and make sure none of the previous pages have an existing rule
+            for (int i = 0; i < pageIndex; i++)
+            {
+                if (rules.Contains(update.Pages[i]))
+                {
+                    isUpdateValid = false;
+                    break;
+                }
+            }
+        }
+
+        return isUpdateValid;
+    }
+
+    public override bool ParseLine(string line, object? context = null)
+    {
+        if (line.Contains('|'))
+        {
+            // It's a rule
+            Rules.Add(new OrderingRule(line));
+        } 
+        else if (!String.IsNullOrWhiteSpace(line))
+        {
+            // Must be an update
+            string[] pages = line.Split(',');
+
+            Updates.Add(new Update(pages));
+        }
+
+        return true;
+    }
+}

2024/Day05CSharp/Properties/launchSettings.json

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+{
+  "profiles": {
+    "Day05CSharp": {
+      "commandName": "Project",
+      "workingDirectory": "C:\\dev\\dev-drive\\DevSandbox\\AdventOfCode\\2024\\Day05CSharp"
+    }
+  }
+}

2024/Day05CSharp/example-input.txt

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+47|53
+97|13
+97|61
+97|47
+75|29
+61|13
+75|53
+29|13
+97|29
+53|29
+61|53
+97|53
+61|29
+47|13
+75|47
+97|75
+47|61
+75|61
+47|29
+75|13
+53|13
+
+75,47,61,53,29
+97,61,53,29,13
+75,29,13
+75,97,47,61,53
+61,13,29
+97,13,75,29,47