[poj] 3090 Visible Lattice Points

#include<cstdio>
#define N 1010
using namespace std;
int x,y,n,f[N],m;

int read()
{
    int ans=0,fu=1;
    char j=getchar();
    for (;(j<'0' || j>'9') && j!='-';j=getchar()) ;
    if (j=='-') fu=-1,j=getchar();
    for (;j>='0' && j<='9';j=getchar()) ans*=10,ans+=j-'0';
    return ans*fu;
}

void init()
{
    f[1]=1;
    for (int i=2;i<=1000;i++)
    if (!f[i])
        for (int j=i;j<=1000;j+=i)
        {
        if (!f[j]) f[j]=j;
        f[j]=f[j]/i*(i-1);
        }
    for (int i=2;i<=1000;i++)
    f[i]+=f[i-1];
}

int main()
{
    init();
    m=read();
    for (int i=1;i<=m;i++)
    {
    n=read();
    printf("%d %d %d\n",i,n,f[n]*2+1);
    }
    return 0;
}