feat: solved day 5 part 2

05/PrintQueue.Tests/PuzzleParserTests.cs

@@ -73,4 +73,22 @@ public class PuzzleParserTests
 
     await Assert.That(result).IsEqualTo(6260);
   }
+  
+  [Test]
+  public async Task Parse_WhenGivenPuzzleInputOnPart2_ItShouldReturnExpectedResult()
+  {
+    var input = await GetPuzzleInput();
+
+    var parseResult = _puzzleParser.Parse(input);
+    
+    var validator = new UpdateValidator(parseResult.Rules);
+
+    var result = parseResult.Updates
+      .Where(u => validator.Validate(u) is false)
+      .Select(u => validator.Sort(u))
+      .Select(u => u.GetMiddlePage())
+      .Sum();
+
+    await Assert.That(result).IsEqualTo(5346);
+  }
 }

05/PrintQueue.Tests/UpdateValidatorTests.cs

@@ -81,4 +81,22 @@ public class UpdateValidatorTests
     await Assert.That(resultTwo).IsFalse();
     await Assert.That(resultThree).IsFalse();
   }
+
+  [Test]
+  public async Task Sort_WhenGivenInvalidUpdate_ItShouldReturnNewUpdateSorted()
+  {
+    var updateOne = new Update([75,97,47,61,53]);
+    var updateTwo = new Update([61,13,29]);
+    var updateThree = new Update([97,13,75,29,47]);
+
+    var validator = new UpdateValidator(_exampleRules);
+    
+    var resultOne = validator.Sort(updateOne);
+    var resultTwo = validator.Sort(updateTwo);
+    var resultThree = validator.Sort(updateThree);
+
+    await Assert.That(resultOne).IsEquivalentTo(new Update([97,75,47,61,53]));
+    await Assert.That(resultTwo).IsEquivalentTo(new Update([61,29,13]));
+    await Assert.That(resultThree).IsEquivalentTo(new Update([97,75,47,29,13]));
+  }
 }

05/PrintQueue/Program.cs

@@ -26,10 +26,16 @@ var parseResult = parser.Parse(input);
 
 var validator = new UpdateValidator(parseResult.Rules);
 
-var result = parseResult.Updates
-  .Where(u => validator.Validate(u))
-  .Select(u => u.GetMiddlePage())
-  .Sum();
+var result = isPart2 
+  ? parseResult.Updates
+      .Where(u => validator.Validate(u) is false)
+      .Select(u => validator.Sort(u))
+      .Select(u => u.GetMiddlePage())
+      .Sum()
+  : parseResult.Updates
+      .Where(u => validator.Validate(u))
+      .Select(u => u.GetMiddlePage())
+      .Sum();
 
 stopwatch.Stop();
 Console.WriteLine($"The sum of the page numbers is {result}. ({stopwatch.ElapsedMilliseconds}ms)");

05/PrintQueue/UpdateValidator.cs

@@ -21,6 +21,30 @@ class UpdateValidator
       Graph[rule.X].Add(rule.Y);
     }
   }
+
+  public Update Sort(Update update)
+  {
+    var sortedUpdate = new Update(update.Pages.ToList());
+
+    while (Validate(sortedUpdate) is false)
+    {
+      for (var i = 0; i < sortedUpdate.Pages.Count - 1; i++)
+      {
+        var currentPage = sortedUpdate.Pages[i];
+        var nextPage = sortedUpdate.Pages[i + 1];
+
+        if (IsOutOfOrder(currentPage, nextPage) is false)
+        {
+          continue;
+        }
+
+        sortedUpdate.Pages[i] = nextPage;
+        sortedUpdate.Pages[i + 1] = currentPage;
+      }
+    }
+
+    return sortedUpdate;
+  }
   
   public bool Validate(Update update)
   {
@@ -28,20 +52,20 @@ class UpdateValidator
     
     foreach (var page in update.Pages)
     {
-      foreach (var previousPage in previousPages)
+      if (previousPages.Any(previousPage => IsOutOfOrder(previousPage, page)))
       {
-        if (
-          Graph.TryGetValue(previousPage, out HashSet<int>? value) &&
-          value.Contains(page) is false
-        )
-        {
-          return false;
-        }
+        return false;
       }
-      
+
       previousPages.Add(page);
     }
     
     return true;
   }
+
+  private bool IsOutOfOrder(int previousPage, int futurePage)
+  {
+    return Graph.TryGetValue(previousPage, out var dependents) &&
+           dependents.Contains(futurePage) is false;
+  }
 }

README.md

@@ -42,9 +42,10 @@ dotnet build
 
 ## Challenges
 
-| Day | Problem                    | Solution                            | Notes                                                                                        |
-|-----|----------------------------|-------------------------------------|----------------------------------------------------------------------------------------------|
+| Day | Problem                    | Solution                           | Notes                                                                                        |
+|-----|----------------------------|------------------------------------|----------------------------------------------------------------------------------------------|
 | 01  | [Problem](./01/PROBLEM.md) | [Solution](./01/HistorianHysteria/) | A great way to start!                                                                        |
-| 02  | [Problem](./02/PROBLEM.md) | [Solution](./02/RedNosedReports/)   | Damn their was an edge case that really bit me...direction change after first pair of levels |
-| 03  | [Problem](./03/PROBLEM.md) | [Solution](./03/MullItOver/)        | Thank goodness this wasn't a repeat of day 2.                                                |
-| 04  | [Problem](./04/PROBLEM.md) | [Solution](./04/CeresSearch/)       | This was fun! Definitely was able to see the growth in my abilities here.                    |
+| 02  | [Problem](./02/PROBLEM.md) | [Solution](./02/RedNosedReports/)  | Damn their was an edge case that really bit me...direction change after first pair of levels |
+| 03  | [Problem](./03/PROBLEM.md) | [Solution](./03/MullItOver/)       | Thank goodness this wasn't a repeat of day 2.                                                |
+| 04  | [Problem](./04/PROBLEM.md) | [Solution](./04/CeresSearch/)      | This was fun! Definitely was able to see the growth in my abilities here.                    |
+| 05  | [Problem](./05/PROBLEM.md) | [Solution](./05/PrintQueue/)       | A graph to the rescue!                                                                       |