POJ 3090 Visible Lattice Points

#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <stack>
#include <map>
#include <set>
#include <vector>
#include <sstream>
#include <queue>
#include <utility>
using namespace std;

#define rep(i,j,k) for (int i=j;i<=k;i++)
#define Rrep(i,j,k) for (int i=j;i>=k;i--)

#define Clean(x,y) memset(x,y,sizeof(x))
#define LL long long
#define ULL unsigned long long
#define inf 0x7fffffff
#define mod %100000007

#define mp make_pair
#define fi first
#define se second

#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define mid int m=(l+r)>>1
const int maxn = 1009;
int mindiv[maxn],phi[maxn];

void getphi(int n)
{
rep(i,1,n) mindiv[i] = i;
for(int i = 2; i*i <= n; i++)
if ( mindiv[i] == i )
{
for(int j = i*i; j <= n; j+=i) mindiv[j] = i;
}
phi[1] = 1;
rep(i,2,n)
{
phi[i] = phi[i/mindiv[i]];
if ( ( i / mindiv[i] ) % mindiv[i] == 0 ) phi[i] *= mindiv[i];
else phi[i] *= ( mindiv[i] - 1 );
}
}

int cal(int n)
{
int ans = 3;
rep(i,2,n) ans += 2*phi[i];
return ans;
}

int main()
{
getphi(1000);
int T,n;
cin>>T;
rep(kase,1,T)
{
scanf("%d",&n);
int ans = cal(n);
printf("%d %d %d\n",kase,n,ans);
}

return 0;
}