Is there a reason Interval is better? Please add a description
https://codereview.appspot.com/571980043/diff/579590043/lily/include/skyline.hh File lily/include/skyline.hh (right): https://codereview.appspot.com/571980043/diff/579590043/lily/include/skyline.hh#newcode36 lily/include/skyline.hh:36: Real end_; Maybe you want to delete end_? https://codereview.appspot.com/571980043/
