P4213 【模板】杜教筛

题面:https://www.luogu.org/problem/P4213

#include
#include
#include
#include
#include
#include
#include
#include
#include
using namespace std;
const int mod=1000000007,N=5000005;
long long phi[N];
int t,prime[N],cnt,mobius[N];
bool vis[N];
unordered_mapans_mobius;
unordered_map ans_phi;
inline int read(){int x=0,f=1;char c=getchar();while(c<'0'||c>'9'){if(c=='-'){f=-1;c=getchar();}}while(c>='0'&&c<='9'){x=x*10+c-48;c=getchar();}return x*f;
}
inline long long get_phi(long long x){if(x<=N){return phi[x];}if(ans_phi[x]){return ans_phi[x];}long long ans=((1+x)*x)/2;for(register int l=2,r;l<=x;l=r+1){r=x/(x/l);ans-=(r-l+1)*get_phi(x/l);}return ans_phi[x]=ans;
}
inline int get_mobius(int x){if(x<=N){return mobius[x];}if(ans_mobius[x]){return ans_mobius[x];}int ans=1;for(register int l=2,r;l<=x;l=r+1){r=x/(x/l);ans-=(r-l+1)*get_mobius(x/l);}return ans_mobius[x]=ans;
}
int main(){mobius[1]=phi[1]=1;for(register int i=2;i<=N;++i){if(!vis[i]){prime[++cnt]=i;mobius[i]=-1;phi[i]=i-1;}for(register int j=1;j<=cnt&&prime[j]*i<=N;++j){vis[prime[j]*i]=1;if(i%prime[j]==0){phi[i*prime[j]]=phi[i]*prime[j];break;}phi[i*prime[j]]=phi[prime[j]]*phi[i];mobius[i*prime[j]]=-mobius[i];}}for(register int i=1;i<=N;++i){mobius[i]+=mobius[i-1];phi[i]+=phi[i-1];}int x;t=read();while(t--){x=read();printf("%lld %d\n",get_phi(x),get_mobius(x));}return 0;
}

转载于:https://www.cnblogs.com/ukcxrtjr/p/11311269.html


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