Please suggest an approach to solve this problem. (Problem Link)
№ | Пользователь | Рейтинг |
---|---|---|
1 | tourist | 3985 |
2 | jiangly | 3885 |
3 | jqdai0815 | 3682 |
4 | Benq | 3580 |
5 | orzdevinwang | 3526 |
6 | ksun48 | 3506 |
7 | ecnerwala | 3505 |
8 | Radewoosh | 3457 |
9 | Kevin114514 | 3377 |
10 | gamegame | 3374 |
Страны | Города | Организации | Всё → |
№ | Пользователь | Вклад |
---|---|---|
1 | cry | 170 |
2 | Um_nik | 162 |
3 | atcoder_official | 161 |
4 | maomao90 | 158 |
4 | -is-this-fft- | 158 |
6 | djm03178 | 157 |
7 | Dominater069 | 156 |
8 | adamant | 154 |
9 | luogu_official | 153 |
10 | awoo | 152 |
Please suggest an approach to solve this problem. (Problem Link)
Название |
---|
Firstly we have to convert the tree queries into array queries. We can perform a dfs and using start and end times , convert the tree to an array. Then each subtree is a range l to r in the array. Now according to the question we have to count the nodes in the subtree rooted at X with value between l to r. That is a range query in array which can be handled using segment tree.
According to me, it was required to run BFS/DFS from node x and check the heights of all nodes in subtree to be in range [L,R]. I constructed a directed graph and followed this approach which gave me WA. Can you tell why this approach is wrong?