Help me please.
I have problem.
Given array.
You have Q queries.
You need to find most frequent number between l and r. n, Q <= 500 000.
№ | Пользователь | Рейтинг |
---|---|---|
1 | ecnerwala | 3648 |
2 | Benq | 3580 |
3 | orzdevinwang | 3570 |
4 | cnnfls_csy | 3569 |
5 | Geothermal | 3568 |
6 | tourist | 3565 |
7 | maroonrk | 3530 |
8 | Radewoosh | 3520 |
9 | Um_nik | 3481 |
10 | jiangly | 3467 |
Страны | Города | Организации | Всё → |
№ | Пользователь | Вклад |
---|---|---|
1 | maomao90 | 174 |
2 | adamant | 164 |
2 | awoo | 164 |
4 | TheScrasse | 160 |
5 | nor | 159 |
6 | maroonrk | 156 |
7 | -is-this-fft- | 150 |
8 | SecondThread | 147 |
9 | orz | 145 |
9 | pajenegod | 145 |
I have problem.
Given array.
You have Q queries.
You need to find most frequent number between l and r. n, Q <= 500 000.
Название |
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What about Time Limit?
Maybe, it can be solved by MO's algorithm with big constant(~5).
Let's maintain:
cntx -> the number of occurance of x,
cntBlockx -> the number of elements, that occurrence lie in this block(if K is size of blocks, occurrence must be between [K * Block: (K + 1) * Block)).
valsx -> the vector with elements, that occurrence is equal to x.
When adding/removing elements, we must update each of them. Deleting can be done in 1 operation. Swap with last, delete last(maintain extra array posx, the position of x in vector).
Finding answer will be ez. Find maximum block mx that, cntBlockmx > 0, find maximum number x in this block, that vals[x].size() > 0.
Sorry for my poor English.
Do you know smth about segment tree?