코드포스 중상급자를 위한 문제 20개를 추천드립니다.

1. [Codeforces 1183C - Flags](https://codeforces.com/problemset/problem/1183/C)

2. [Codeforces 1328D - Carousel](https://codeforces.com/problemset/problem/1328/D)

3. [Codeforces 1389D - Captain Flint and a Long Voyage](https://codeforces.com/problemset/problem/1389/D)

4. [Codeforces 1332D - Walk on Matrix](https://codeforces.com/problemset/problem/1332/D)

5. [Codeforces 1399D - Banned K](https://codeforces.com/problemset/problem/1399/D)

6. [Codeforces 1397D - Juggling Letters](https://codeforces.com/problemset/problem/1397/D)

7. [Codeforces 1339D - Yet Another Yet Another Task](https://codeforces.com/problemset/problem/1339/D)

8. [Codeforces 1333D - Challenges in school No 41](https://codeforces.com/problemset/problem/1333/D)

9. [Codeforces 1401D - Maximum Distributed Tree](https://codeforces.com/problemset/problem/1401/D)

10. [Codeforces 1398D - Colored Rectangles](https://codeforces.com/problemset/problem/1398/D)

11. [Codeforces 1373D - Maximum Sum on Even Positions](https://codeforces.com/problemset/problem/1373/D)

12. [Codeforces 1369D - TediousLee](https://codeforces.com/problemset/problem/1369/D)

13. [Codeforces 1372D - Omkar and Bed Wars](https://codeforces.com/problemset/problem/1372/D)

14. [Codeforces 1374D - Zero Remainder Array](https://codeforces.com/problemset/problem/1374/D)

15. [Codeforces 1375D - Replace by MEX](https://codeforces.com/problemset/problem/1375/D)

16. [Codeforces 1366D - Johnny and Contribution](https://codeforces.com/problemset/problem/1366/D)

17. [Codeforces 1379D - Rarity and New Dress](https://codeforces.com/problemset/problem/1379/D)

18. [Codeforces 1404D - Zigzags](https://codeforces.com/problemset/problem/1404/D)

19. [Codeforces 1388D - Captain Flint and Treasure](https://codeforces.com/problemset/problem/1388/D)

20. [Codeforces 1354D - Multiset](https://codeforces.com/problemset/problem/1354/D)