http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0627 解説 https://www.ioi-jp.org/joi/2015/2016-ho/2016-ho-t3-review.pdf
http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0627
解説
https://www.ioi-jp.org/joi/2015/2016-ho/2016-ho-t3-review.pdf