I created a video editorial talking about how to use Atcoder Library's Segment Tree to optimize CF2019D: Speedbreaker
→ Обратите внимание
→ Трансляции
→ Лидеры (рейтинг)
| № | Пользователь | Рейтинг |
|---|---|---|
| 1 | Benq | 3676 |
| 2 | jiangly | 3670 |
| 3 | Kevin114514 | 3657 |
| 4 | maroonrk | 3355 |
| 5 | Um_nik | 3353 |
| 6 | squareOf105 | 3346 |
| 7 | tourist | 3343 |
| 8 | strapple | 3324 |
| 9 | heuristica | 3322 |
| 10 | jiangbowen | 3291 |
| Страны | Города | Организации | Всё → |
→ Лидеры (вклад)
| № | Пользователь | Вклад |
|---|---|---|
| 1 | Qingyu | 158 |
| 2 | nik_exists | 150 |
| 2 | maspy | 150 |
| 4 | AmShZ | 143 |
| 5 | Um_nik | 141 |
| 6 | Errichto | 139 |
| 7 | adamant | 137 |
| 8 | BledDest | 133 |
| 8 | maroonrk | 133 |
| 10 | qwexd | 130 |
→ Найти пользователя
→ Прямой эфир
Codeforces (c) Copyright 2010-2026 Михаил Мирзаянов
Соревнования по программированию 2.0
Время на сервере: 14.10.2026 02:01:48 (g2).
Десктопная версия, переключиться на мобильную.
При поддержке
Very hard problems
I dont get it, D was extremely simple. You just have to track the first and last occursnce of each character, and then keep intersecting the segments.
A 20 line implementation would reach $$$O(n)$$$ without segment trees on this problem.
Yes, I agree Segment Tree might be an overkill for this problem. However, I arrived at the segtree solution without a lot of efforts, hence wanted to share an alternate solution from the editorial.
Also, looking at submission count of Problem C (6529) vs Problem D (1373), a lot of people did not submit the overkill segtree solution, possibly because they were not aware of such data structures or thought process of reducing the problem to a standard domain, hence the video.
Yes it's always useful to learn different ways to solve a problem.