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typedef long long lint; | |
namespace fft{ | |
typedef complex<double> base; | |
void fft(vector<base> &v, bool inv){ | |
vector<base> w(v.size()); | |
for(int i=2; i<=v.size(); i<<=1){ | |
int bsz = v.size() / i; | |
base ang(cos(2 * M_PI / i), sin(2 * M_PI / i)); | |
if(inv) ang = base(1, 0) / ang; | |
for(int j=0; j<bsz; j++){ | |
for(int k=0; k<i; k++){ | |
w[k] = v[bsz * k + j]; | |
} | |
base pw(1, 0); | |
for(int k=0; k<i/2; k++){ | |
base a = w[2*k], b = w[2*k+1] * pw; | |
v[bsz * k + j] = a + b; | |
v[bsz * k + j + v.size()/2] = a - b; | |
pw *= ang; | |
} | |
} | |
} | |
if(inv){ | |
for(int i=0; i<v.size(); i++){ | |
v[i] /= v.size(); | |
} | |
} | |
} | |
vector<lint> multiply(vector<lint> &v, vector<lint> &w){ | |
vector<base> fv(v.begin(), v.end()), fw(w.begin(), w.end()); | |
int n = 1; | |
while(n < max(v.size(), w.size())) n <<= 1; | |
n <<= 1; | |
fv.resize(n); | |
fw.resize(n); | |
fft(fv, 0); | |
fft(fw, 0); | |
for(int i=0; i<n; i++) fv[i] *= fw[i]; | |
fft(fv, 1); | |
vector<lint> ret(n); | |
for(int i=0; i<n; i++) ret[i] = round(fv[i].real()); | |
return ret; | |
} | |
vector<lint> power(vector<lint> &v){ | |
vector<base> fv(v.begin(), v.end()); | |
int n = 1; | |
while(n < v.size()) n <<= 1; | |
n <<= 1; | |
fv.resize(n); | |
fft(fv, 0); | |
for(int i=0; i<n; i++) fv[i] *= fv[i]; | |
fft(fv, 1); | |
vector<lint> ret(n); | |
for(int i=0; i<n; i++) ret[i] = round(fv[i].real()); | |
return ret; | |
} | |
}; |
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