§ Vandermonde and FFT
FFT lets you do the following:
You are given two sequences:
b0,...,bm Compute sequence
c0,…,c[n+m] such that
This is exactly what I needed here, where and .
If I thought for a little longer I would realize that
instead of computing it using FFT.
- [Codeforces contest comment by Swistakk)[https://codeforces.com/blog/entry/85348?#comment-730898]