feat: solved day 3

03/MullItOver/InstructionExtensions.cs

@@ -0,0 +1,28 @@
+namespace MullItOver;
+
+public static class InstructionExtensions
+{
+  public static int Execute(this List<Instruction> instructions)
+  {
+    var isEnabled = true;
+    var sum = 0;
+
+    foreach (var instruction in instructions)
+    {
+      switch (instruction)
+      {
+        case DontInstruction:
+          isEnabled = false;
+          continue;
+        case DoInstruction:
+          isEnabled = true;
+          continue;
+        case MulInstruction mul when isEnabled:
+          sum += mul.Execute();
+          continue;
+      }
+    }
+    
+    return sum;
+  }
+}