提交记录 22533


用户 题目 状态 得分 用时 内存 语言 代码长度
zjy0001 1002. 测测你的多项式乘法 Accepted 100 218.894 ms 48432 KB C++17 4.41 KB
提交时间 评测时间
2024-09-25 13:55:28 2024-09-25 13:55:31
#include<bits/stdc++.h>
#define LL long long
#define LLL __int128
#define uint unsigned
#define ldb long double
#define uLL unsigned long long
using namespace std;
typedef vector<int> poly;
typedef vector<int> Vec;
typedef vector<Vec> Mat;
typedef tuple<poly,poly> Vec2;
typedef tuple<poly,poly,poly,poly> Mat2;
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
const int Mod=998244353,G=3,img=86583718;
const int winv=ULLONG_MAX%Mod+1,rinv=2-Mod;
const LL Mod2=(LL)Mod*Mod;
poly Grt({1}),Grt0,Grt1,frc({1,1}),inv({0,1}),ivf({1,1});vector<poly>Tr,Ts;
inline int fadd(const int&x,const int&y){int z=x+y;return z<0?z+Mod:z-Mod;}
inline int fsub(const int&x,const int&y){int z=x-y;return z<0?z+Mod:z-Mod;}
inline int reduce(const LL&x){return (x>>32)-(((LL)((int)(x*rinv))*Mod)>>32);}
inline int qpow(int x,int y,int z=1){
	for(;y;(y>>=1)&&(x=(LL)x*x%Mod))if(y&1)z=(LL)z*x%Mod;return z;
}
inline void Init(const int&n){
	for(int i=frc.size();i<=n;++i)
		frc.emplace_back((LL)frc.back()*i%Mod),
		inv.emplace_back(Mod-Mod/i*(LL)inv[Mod%i]%Mod),
		ivf.emplace_back((LL)ivf.back()*inv.back()%Mod);
}
inline int Binom(const int&n,const int&m){
	if(n<m||m<0)return 0;
	return Init(n),(LL)frc[n]*ivf[m]%Mod*ivf[n-m]%Mod;
}
inline int BSGS(int x){
	unordered_map<int,int>mp;
	int S=sqrtl(Mod)+1,j=1,q=1;
	for(int i=0;i<S;++i,j=(LL)j*G%Mod)mp[(LL)j*x%Mod]=i;
	for(int i=0;i<=S;++i,q=(LL)q*j%Mod)if(mp.count(q)&&i*S>=mp[q])return i*S-mp[q];
	return -1;
}
inline poly Add(poly P,poly Q){
    if(P.size()<Q.size())swap(P,Q);
    for(int i=Q.size();i--;)(P[i]+=Q[i])>=Mod&&(P[i]-=Mod);
    return P;
}
inline poly Sub(poly P,poly Q){
    if(P.size()<Q.size())P.resize(Q.size());
    for(int i=Q.size();i--;)(P[i]-=Q[i])<0&&(P[i]+=Mod);
    return P;
}
inline poly Neg(poly P){
	for(int i=P.size();i--;)P[i]&&(P[i]=Mod-P[i]);
	return P;
}
inline bool Empty(poly&P){
	for(;!P.empty()&&!P.back();P.pop_back());
	return P.empty();
}
inline int Eval(poly&P,int x){
	int z=0;
	for(int i=P.size();i--;)z=((LL)z*x+P[i])%Mod;
	return z;
}
inline Mat operator*(const Mat&x,const Mat&y){
	const int n=x.size(),m=y.size(),q=y[0].size();
	Mat z(n,Vec(q));
	for(int i=0;i<n;++i)for(int j=0;j<m;++j)if(x[i][j])
		for(int k=0;k<q;++k)z[i][k]=(z[i][k]+(LL)x[i][j]*y[j][k])%Mod;
	return z;
}
inline void dftdfs(poly&P,int i,int k){
	if(k==1)return;
	const int R=k,R4=R/4;
	int*P0=&P[i*R],*P1=P0+R4,*P2=P1+R4,*P3=P2+R4;
	const int g20=Grt1[i+i],gg0=Grt0[i+i],g21=Grt1[i+i+1],gg1=Grt0[i+i+1],g2=Grt1[i],gg=Grt0[i];
	for(int j=0,z=0,m=0,z0=0,z1=0,z2=0,z3=0,s0=0,d0=0,s1=0,d1=0;j<R4;++j){
		z=P2[j],m=(uint)g2*z,z0=((LL)z*gg-(LL)m*Mod)>>32;
		z=P3[j],m=(uint)g2*z,z1=((LL)z*gg-(LL)m*Mod)>>32;
		s0=fadd(P0[j],z0),d0=fsub(P0[j],z0),s1=P1[j]+z1,d1=P1[j]-z1;
		z=s1,m=(uint)g20*z,z2=((LL)z*gg0-(LL)m*Mod)>>32;
		z=d1,m=(uint)g21*z,z3=((LL)z*gg1-(LL)m*Mod)>>32;
		P0[j]=fadd(s0,z2),P1[j]=fsub(s0,z2),P2[j]=fadd(d0,z3),P3[j]=fsub(d0,z3);
	}
	dftdfs(P,i*4+0,k/4),dftdfs(P,i*4+1,k/4),dftdfs(P,i*4+2,k/4),dftdfs(P,i*4+3,k/4);
}
inline void dft(poly&P){
	const int m=P.size(),n=m,n2=n/2;
    int L=Grt.size();
	if(L*2<n)for(Grt.resize(n2);L*2<n;L<<=1){
		const int cr=qpow(G,Mod/(L<<2));
		for(int i=0;i<L;++i)Grt[i+L]=(LL)cr*Grt[i]%Mod;
	}
	if(Grt0.size()<Grt.size()){
		const int pr=Grt0.size(),ed=Grt.size();
		Grt0.resize(ed),Grt1.resize(ed);
		for(int i=pr;i<ed;++i)
			Grt0[i]=reduce((LL)winv*Grt[i]),Grt1[i]=(uint)rinv*Grt0[i];
	}
	if(__lg(n)&1){
		const int R2=n2;
		for(int i=0;i<R2;++i){
			const int j=i+R2,v=fsub(P[i],P[j]);
			P[i]=fadd(P[i],P[j]),P[j]=v;
		}
		dftdfs(P,0,n2),dftdfs(P,1,n2);
	}
	else dftdfs(P,0,n);
    for(int&i:P)(i<0&&(i+=Mod));
}
inline void idft(poly&P){
	const int m=P.size(),n=m,ni=reduce((LL)qpow(n,Mod-2)*winv),n2=n/2;
	poly rev(n);
	for(int i=1;i<n;++i)rev[i]=(rev[i>>1]>>1)+(i&1)*n2;
	for(int&i:P)i=reduce((LL)i*ni);
	for(int i=1;i<n;++i)if(i<rev[i])swap_ranges(P.begin()+i,P.begin()+(i+1),P.begin()+rev[i]);
	for(int i=1;i<n2;++i)swap_ranges(P.begin()+i,P.begin()+(i+1),P.begin()+(n-i));
	dft(P);
	for(int i=1;i<n;++i)if(i<rev[i])swap_ranges(P.begin()+i,P.begin()+(i+1),P.begin()+rev[i]);
}
inline poly Mul(poly P,poly Q){
    if(P.empty()||Q.empty())return poly();
	const int pn=P.size(),qn=Q.size(),rn=pn+qn-1;
	int m=1;while(m<rn)m*=2;
	P.resize(m),Q.resize(m);
	dft(P),dft(Q);
	for(int i=m;i--;)P[i]=(LL)P[i]*Q[i]%Mod;
	idft(P);
	return P.resize(rn),P;
}
void poly_multiply(unsigned *a, int n, unsigned *b, int m, unsigned *c)
{
	poly P=Mul(poly(a,a+n+1),poly(b,b+m+1));
copy(P.begin(),P.end(),c);
}

CompilationN/AN/ACompile OKScore: N/A

Testcase #1218.894 ms47 MB + 304 KBAcceptedScore: 100


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