code: private static Point2d[] coordinatesOfCycle(int[] cycle, IAtomContainer container) {
          Point2d[] points = new Point2d[cycle.length];
          for (int i = 0; i < cycle.length; i++) {
              points[i] = container.getAtom(cycle[i]).getPoint2d();
          }
          return points;
      }
docs: Obtain the coordinates of atoms in a cycle.
  
  @param cycle     vertices that form a cycles
  @param container structure representation
  @return coordinates of the cycle