摘要：FFT https://www.luogu.org/problemnew/solution/P3723 重点在于构造卷积的形式 cpp include include include include include include using namespace std; const int MAX 阅读全文

摘要：FFT $$E_i = F_i / q_i = \sum_{i j} \frac{q _ j} {(i j)^2}$$ 设 $p _ i = q_{n i}$ $g(i) = \frac 1 {i^2}$ 则 $E_i = \sum_{j=1}^{i 1} q _ i g(j i) \sum _ { 阅读全文

摘要：讲解:http://www.cnblogs.com/poorpool/p/8760748.html 递归版FFT cpp include include include include include include using namespace std; const int MAXN = 400 阅读全文