Day6 optimisation

Advent24/Day6.cs

@@ -235,14 +235,19 @@ namespace Advent24
 
                 // remove already-checked linear positions from visited
                 // so it only has new positions to add to our uncheckedLinearPositions
-                visited.ExceptWith(checkedLinearPositions);
+                // This line isn't required because we're only adding one additional obstacle, which
+                // will only affect the original path (which we're already checking)
+                //visited.ExceptWith(checkedLinearPositions);
 
                 previousUncheckedLinearPositionsCount = uncheckedLinearPositions.Count;
 
                 // update uncheckedLinearPositions to remove firstNonCheckedLinearPosition
                 // and add newly visisted linear positions
                 uncheckedLinearPositions.Remove(firstNonCheckedLinearPosition);
-                uncheckedLinearPositions.UnionWith(visited);
+                
+                // This line isn't required because we're only adding one additional obstacle, which
+                // will only affect the original path (which we're already checking)
+                //uncheckedLinearPositions.UnionWith(visited);
 
              // if (uncheckedLinearPositions.Count > previousUncheckedLinearPositionsCount)
              //     Console.WriteLine("(change) uncheckedLinearPositions.Count = {0:d}", uncheckedLinearPositions.Count - previousUncheckedLinearPositionsCount);