| # | User | Rating |
|---|---|---|
| 1 | ecnerwala | 3650 |
| 2 | Benq | 3582 |
| 3 | Geothermal | 3570 |
| 3 | orzdevinwang | 3570 |
| 5 | cnnfls_csy | 3569 |
| 6 | tourist | 3565 |
| 7 | maroonrk | 3532 |
| 8 | Radewoosh | 3522 |
| 9 | Um_nik | 3483 |
| 10 | jiangly | 3468 |
| # | User | Contrib. |
|---|---|---|
| 1 | maomao90 | 174 |
| 2 | awoo | 164 |
| 3 | adamant | 163 |
| 4 | TheScrasse | 159 |
| 5 | nor | 158 |
| 6 | maroonrk | 156 |
| 7 | -is-this-fft- | 151 |
| 8 | SecondThread | 147 |
| 9 | orz | 146 |
| 10 | pajenegod | 145 |
Persistent Segment trees (number of distinct elements in a subarray)
hello everyone,
Recently i came across this problem http://www.spoj.com/problems/DQUERY/en/. I coded the offline solution, but i was wondering how to solve it using persisent segment trees.I kept an array last_occur[i] which stores the latest occurence of the number i. now given a range (l,r) we need to find number of distinct elements with last_occur[i] < l.I got stuck here, how do we solve this part?
