- https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=5239
- コード https://github.com/dohatsutsu/cpro/blob/master/LiveArchive/p7227.cpp
- https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=5244
- 解説 http://dohatsutsu.hatenablog.com/entry/2016/07/04/235531
- コード https://github.com/dohatsutsu/cpro/blob/master/LiveArchive/p7232.cpp