SPOJ VLATTICE - Visible Lattice Points 莫比乌斯反演

VLATTICE - Visible Lattice Points

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Consider a N*N*N lattice. One corner is at (0,0,0) and the opposite one is at (N,N,N). How many lattice points are visible from corner at (0,0,0) ? A point X is visible from point Y iff no other lattice point lies on the segment joining X and Y. 
 
Input : 
The first line contains the number of test cases T. The next T lines contain an interger N 
 
Output : 
Output T lines, one corresponding to each test case. 
 
Sample Input : 
3 
1 
2 
5 
 
Sample Output : 
7 
19 
175 
 
Constraints : 
T <= 50 
1 <= N <= 1000000

/* ***********************************************
Author        :CKboss
Created Time  :2015年03月26日 星期四 21时56分19秒
File Name     :VLATTICE.cpp
************************************************ */

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <string>
#include <cmath>
#include <cstdlib>
#include <vector>
#include <queue>
#include <set>
#include <map>

using namespace std;

typedef long long int LL;

const int maxn = 1001000;

bool check[maxn];
int prime[maxn],mu[maxn];

void Moblus()
{
	memset(check,true,sizeof(check));
	mu[1]=1;
	int tot=0;
	for(int i=2;i<maxn;i++)
	{
		if(check[i])
		{
			prime[tot++]=i; mu[i]=-1;
		}
		for(int j=0;j<tot;j++)
		{
			int ij=prime[j]*i;
			if(ij>maxn) break;
			check[ij]=false;
			if(i%prime[j]==0)
			{
				mu[ij]=0; break;
			}
			else mu[ij]=-mu[i];
		}
	}
}


int main()
{
    //freopen("in.txt","r",stdin);
    //freopen("out.txt","w",stdout);

	Moblus();

	int T_T;
	cin>>T_T;
	while(T_T--)
	{
		LL n;
		cin>>n;
		LL sum=3;
		for(int i=1;i<=n;i++)
		{
			sum+=mu[i]*(n/i)*(n/i)*(n/i+3);
		}
		cout<<sum<<endl;
	}
    
    return 0;
}