| # | User | Rating |
|---|---|---|
| 1 | tourist | 3985 |
| 2 | jiangly | 3741 |
| 3 | jqdai0815 | 3682 |
| 4 | Benq | 3529 |
| 5 | orzdevinwang | 3526 |
| 6 | ksun48 | 3489 |
| 7 | Radewoosh | 3483 |
| 8 | Kevin114514 | 3442 |
| 9 | ecnerwala | 3392 |
| 9 | Um_nik | 3392 |
| # | User | Contrib. |
|---|---|---|
| 1 | cry | 169 |
| 2 | maomao90 | 162 |
| 2 | Um_nik | 162 |
| 2 | atcoder_official | 162 |
| 5 | djm03178 | 158 |
| 6 | -is-this-fft- | 157 |
| 7 | adamant | 155 |
| 8 | awoo | 154 |
| 8 | Dominater069 | 154 |
| 10 | nor | 150 |
How to efficiently count specific regular bracket sequences?
I came up on a problem and got it to solving this one, but now I am stuck. Can someone help please?
How can we efficiently count the number of regular bracket sequences with length $$$2n$$$ that have first closing bracket on position $$$k + 1$$$ (any way faster than $$$O(nk)$$$ or $$$O(n^2))$$$?
