2020-05-28 今日の精進 2020/05/27 Div2バチャ ABDの3完 https://codeforces.com/contest/691 復習 atcoder.jp 青diffバチャ 2完 https://kenkoooo.com/atcoder/#/contest/show/1f37c5a8-8da7-415d-ab60-633bb22af2e3