poj 3090 Visible Lattice Points

#include<iostream>
#include<algorithm>
using namespace std;
 const int M=1e6;
 int vis[M+4],P[M+4],cnt;
 int fi[M+4];
 
 void shai(int top){
 	cnt=0;
 	fi[1]=1;
 	for(int i=2;i<=top;i++){
 		if(vis[i]==0){
 			P[++cnt]=i; 
 			fi[i]=i-1;
		 }
 		for(int j=1;j<=cnt&&i*P[j]<=top;j++){
 			vis[i*P[j]]=1;
 			if(i%P[j]==0){
 				fi[i*P[j]]=fi[i]*P[j];
 				break;
			 }
			else
			fi[i*P[j]]=fi[i]*(P[j]-1);
		 }
	 }
 }
 int sum[M+4];
 int main(){
 	shai(1e6);
 	for(int i=1;i<=1e6;i++) 
	 sum[i]=sum[i-1]+fi[i];
 	
 	int tes,cas=0;cin>>tes;
 	while(tes--){
 		int x;
 		cin>>x;
 		cout<<++cas<<' '<<x<<' '<<2*sum[x]+1<<endl;
	 }
 }