标签:class str sample log led tor int style mic
Constraints
1 <= T <= 300000
1 <= n <= 1000000
题解:好吧我naive了,别人都用欧拉函数就我用莫比乌斯反演,还是写一发吧~
然后线性筛∑μ(d)d,然后O(nlogn)枚举n的约数就行了
#include <cstdio> #include <cstring> #include <iostream> #include <vector> using namespace std; const int m=1000000; typedef long long ll; int n,T,num,tot; int pri[m/10],to[m*14],next[m*14],head[m+10]; bool np[m+10]; vector<int> v[m+10]; ll sm[m+10],ans; int main() { int i,j; for(i=1;i<=m;i++) for(j=i;j<=m;j+=i) to[++tot]=i,next[tot]=head[j],head[j]=tot; sm[1]=1; for(i=2;i<=m;i++) { if(!np[i]) pri[++num]=i,sm[i]=1-i; for(j=1;j<=num&&i*pri[j]<=m;j++) { np[i*pri[j]]=1; if(i%pri[j]==0) { sm[i*pri[j]]=sm[i]; break; } sm[i*pri[j]]=sm[i]*(1ll-pri[j]); } } scanf("%d",&T); while(T--) { scanf("%d",&n),ans=0; for(i=head[n];i;i=next[i]) ans+=sm[n/to[i]]*to[i]*(to[i]+1)>>1; printf("%lld\n",ans*n); } return 0; }
【BZOJ2226】[Spoj 5971] LCMSum 莫比乌斯反演(欧拉函数?)
标签:class str sample log led tor int style mic
原文地址:http://www.cnblogs.com/CQzhangyu/p/7008252.html