#include #include #include #include #include using namespace std;const double PI = acos(-1);typedef complex cpx;void FFT(vector &f, cpx w){ int n = f.size(); if(n == 1) return; vector even(n / 2), odd(n / 2); for(int i=0; i multiply(vector a, vector b){ int n = 1; while(n c(n); cpx w(cos(2 * PI / n), sin(2 * PI / n)); FFT(a, w); FFT(b, w); for(int i=0; i> A >> B; ..