链接
luogu
思路
为了做hdu来学杜教筛。
杜教筛模板题。
卡常数，我加了register居然跑到不到800ms。
太深了。
代码
// luogu-judger-enable-o2
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int _=5000030;
int vis[_],pri[_],cnt,N,limit,mu[_];
ll phi[_];
unordered_map<int,ll> ans_phi;
unordered_map<int,ll> ans_mu;
inline void Euler() {vis[1]=phi[1]=mu[1]=1;for(register int i=1;i<=limit;++i) {if(!vis[i]) pri[++cnt]=i,mu[i]=-1,phi[i]=i-1;for(register int j=1;j<=cnt&&i*pri[j]<=limit;++j) {vis[i*pri[j]]=1;if(i%pri[j]==0) {mu[i*pri[j]]=0;phi[i*pri[j]]=phi[i]*pri[j];break;} else {mu[i*pri[j]]=-mu[i];phi[i*pri[j]]=phi[i]*(pri[j]-1);}}}for(register int i=2;i<=limit;++i) mu[i]+=mu[i-1],phi[i]+=phi[i-1];
}
ll Solvephi(register int n) {if(n<=limit) return phi[n];if(ans_phi[n]) return ans_phi[n];register ll tmp=1LL*n*(n+1)/2;for(register int l=2,r;l<=n;l=r+1)r=n/(n/l),tmp-=Solvephi(n/l)*(r-l+1);return ans_phi[n]=tmp;
}
ll Solvemu(register int n) {if(n<=limit) return mu[n]; if(ans_mu[n]) return ans_mu[n];register ll tmp=1;for(register int l=2,r;l<=n;l=r+1)r=n/(n/l),tmp-=Solvemu(n/l)*(r-l+1);return ans_mu[n]=tmp;
}
int main() {int T;cin>>T;limit=5000000;Euler();while(T --> 0) {cin>>N;printf("%lld %lld\n",Solvephi(N),Solvemu(N));}return 0;
}
)
