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arbitrarymod.cpp
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/
arbitrarymod.cpp
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#ifndef call_from_test
#include <bits/stdc++.h>
using namespace std;
#define call_from_test
#include "fastfouriertransform.cpp"
#undef call_from_test
#endif
//BEGIN CUT HERE
template<typename T>
struct ArbitraryMod{
using dbl=FFT::dbl;
using num=FFT::num;
vector<T> multiply(vector<T> as,vector<T> bs){
int need=as.size()+bs.size()-1;
int sz=1;
while(sz<need) sz<<=1;
vector<num> fa(sz),fb(sz);
for(int i=0;i<(int)as.size();i++)
fa[i]=num(as[i].v&((1<<15)-1),as[i].v>>15);
for(int i=0;i<(int)bs.size();i++)
fb[i]=num(bs[i].v&((1<<15)-1),bs[i].v>>15);
fft(fa);fft(fb);
dbl ratio=0.25/sz;
num r2(0,-1),r3(ratio,0),r4(0,-ratio),r5(0,1);
for(int i=0;i<=(sz>>1);i++){
int j=(sz-i)&(sz-1);
num a1=(fa[i]+conj(fa[j]));
num a2=(fa[i]-conj(fa[j]))*r2;
num b1=(fb[i]+conj(fb[j]))*r3;
num b2=(fb[i]-conj(fb[j]))*r4;
if(i!=j){
num c1=(fa[j]+conj(fa[i]));
num c2=(fa[j]-conj(fa[i]))*r2;
num d1=(fb[j]+conj(fb[i]))*r3;
num d2=(fb[j]-conj(fb[i]))*r4;
fa[i]=c1*d1+c2*d2*r5;
fb[i]=c1*d2+c2*d1;
}
fa[j]=a1*b1+a2*b2*r5;
fb[j]=a1*b2+a2*b1;
}
fft(fa);fft(fb);
vector<T> cs(need);
using ll = long long;
for(int i=0;i<need;i++){
ll aa=T(llround(fa[i].x)).v;
ll bb=T(llround(fb[i].x)).v;
ll cc=T(llround(fa[i].y)).v;
cs[i]=T(aa+(bb<<15)+(cc<<30));
}
return cs;
}
};
//END CUT HERE
#ifndef call_from_test
signed main(){
return 0;
}
#endif