24

lib/include/aocpp/Coord.hpp

@@ -40,6 +40,8 @@ auto CW(Coord) -> Coord;
 /// Rotate counter-clockwise
 auto CCW(Coord) -> Coord;
 
+auto Turn180(Coord) -> Coord;
+
 auto Norm1(Coord) -> std::int64_t;
 
 /// Add two coordinates pairwise

lib/src/Coord.cpp

@@ -62,9 +62,11 @@ auto CW(Coord c) -> Coord {
 }
 
 auto CCW(Coord c) -> Coord {
-  c = Invert(c);
-  c.y = -c.y;
-  return c;
+  return CW(CW(CW(c)));
+}
+
+auto Turn180(Coord c) -> Coord {
+  return CW(CW(c));
 }
 
 auto Norm1(Coord c) -> std::int64_t {