feat: solve day 5 part 1

05/PrintQueue/UpdateValidator.cs

@@ -0,0 +1,47 @@
+namespace PrintQueue;
+
+class UpdateValidator
+{
+  public readonly Dictionary<int, HashSet<int>> Graph = [];
+
+  public UpdateValidator(List<OrderRule> rules)
+  {
+    foreach (var rule in rules)
+    {
+      if (Graph.ContainsKey(rule.X) is false)
+      {
+        Graph.Add(rule.X, []);
+      }
+
+      if (Graph.ContainsKey(rule.Y) is false)
+      {
+        Graph.Add(rule.Y, []);
+      }
+      
+      Graph[rule.X].Add(rule.Y);
+    }
+  }
+  
+  public bool Validate(Update update)
+  {
+    var previousPages = new List<int>();
+    
+    foreach (var page in update.Pages)
+    {
+      foreach (var previousPage in previousPages)
+      {
+        if (
+          Graph.TryGetValue(previousPage, out HashSet<int>? value) &&
+          value.Contains(page) is false
+        )
+        {
+          return false;
+        }
+      }
+      
+      previousPages.Add(page);
+    }
+    
+    return true;
+  }
+}