2017-03-28 Educational Codeforces #18: E. Colored Balls http://codeforces.com/contest/792/problem/E 続きを読む
2017-03-16 Codeforces #404 E. Anton and Permutation http://codeforces.com/contest/785/problem/E 続きを読む
2017-03-08 CSAcademy #20 Palindromic Concatenation https://csacademy.com/contest/round-20/#task/palindromic-concatenation 続きを読む