Hello, could someone please explain this problem 450B - Jzzhu and Sequences to me. I've read the editorial and some other peoples code, but I'm not sure I completely understand it. Thanks in advance!
# | User | Rating |
---|---|---|
1 | tourist | 3993 |
2 | jiangly | 3743 |
3 | orzdevinwang | 3707 |
4 | Radewoosh | 3627 |
5 | jqdai0815 | 3620 |
6 | Benq | 3564 |
7 | Kevin114514 | 3443 |
8 | ksun48 | 3434 |
9 | Rewinding | 3397 |
10 | Um_nik | 3396 |
# | User | Contrib. |
---|---|---|
1 | cry | 167 |
2 | Um_nik | 163 |
3 | maomao90 | 162 |
3 | atcoder_official | 162 |
5 | adamant | 159 |
6 | -is-this-fft- | 158 |
7 | awoo | 156 |
8 | TheScrasse | 154 |
9 | Dominater069 | 153 |
10 | nor | 152 |
Hello, could someone please explain this problem 450B - Jzzhu and Sequences to me. I've read the editorial and some other peoples code, but I'm not sure I completely understand it. Thanks in advance!
Name |
---|
Notice that the relation f[i] = f[i+1] + f[i-1] can be rewritten as f[i+1] = f[i] — f[i-1]. We can now calculate f[i] just by using the rewritten relation. After calculating the first 8 terms of f, we get the numbers: x, y, y-x, -x, -y, x-y, x, y. Notice that f repeats itself; to be more precise, f[i+6] = f[i] for any i, so we can just take n modulo 6 and print the corresponding number from the first 6 terms of f.
Thank you
Another thing apart from the already present comments, learn matrix exponentiation method for fibonacci numbers. Similar idea will work here.