[洛谷P4721]分治FFT

NTT入门，放个板子

// luogu-judger-enable-o2
#include <bits/stdc++.h>
using namespace std;
#define fr(i, a, b) for ( int i = a; i <= b; ++ i)
#define mid ( l + r >> 1)
typedef long long ll;
, mod = , Ge = ;
template <class T> void G(T &x) {
    x = ; ; ;
    ) + (x << ) + (o & ); x *= f;
}
ll n, g[], f[], a[], b[], rev[];
ll w[][];
ll _pow(ll x, ll n) { ll ans = ; , x = x * x % P) ) ans = ans * x % P; return ans;}
inline void NTT(ll *a, int n, int f) {
    ; i < n; ++ i) if( i < rev[i]) swap(a[i], a[rev[i]]);
    w[][] = w[][] = ;
    ; i < n; i++) {
        w[][i] = w[][i - ] * _pow(Ge, (P - ) / n) % P;
        w[][i] = _pow(w[][i], P - );
    }
 
    ; i < n; i <<= )
    , l = n / (i << ); j < n; j += (i << ))
    , t = ; k < i; k += , t += l) {
        ll x = a[j + k], y = w[f][t] * a[i + j + k] % P;
        a[j + k] = (x + y) % P, a[i + j + k] = (x - y + P) % P;
    }
 
    ; f && i < n; i++)
        a[i] = a[i] * _pow(n, P - ) % P;
}
inline void cdq(int l, int r) {
    if( l == r) return ;
    cdq(l, mid);
    , L = ;
    ) << ; Len <<= ) ++ L;
    fr(i, , Len) rev[i] = (rev[i >> ] >> )|((i&) << L-);
    fr(i, , Len) a[i] = b[i] = ;
    fr(i, l, mid) a[i-l] = f[i];
    fr(i, , r-l) b[i] = g[i];
    NTT(a, Len, ); NTT(b, Len, );
    fr(i, , Len) a[i] = a[i] * b[i] % P;
    NTT(a, Len, );
    fr(i, mid+, r) f[i] = (f[i] + a[i-l]) % mod;
    cdq(mid+, r);
}
 
int main() {
    G(n); fr(i, , n-) G(g[i]);
    f[] = ; cdq(, n-);
    fr(i, , n-) printf("%lld ", f[i]);
}

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