hdu 2841 Visible Trees

/**
大意： 求[1，m]， [1，n]  之间有多少个数互素。。。做了 1695 ，，这题就so easy 了
**/
#include <iostream>
#include <cmath>
#include <algorithm>
using namespace std;
const long long  maxn = 100050;
long long phi[maxn];
long long priD[maxn];
int len ;

void euler(long long  n){
    long long  m = (int )sqrt(n+0.5);
    len =0;
    for(int i=2;i<=m;i++)if(n%i==0){
        priD[len++] = i;
        while(n%i==0)
            n = n/i;
    }
    if(n>1)
        priD[len++] = n;
}

void phi_table(){
    for(int i=2;i<maxn;i++)
        phi[i] =0;
    phi[1] =1;
    for(int i=2;i<maxn;i++)if(!phi[i]){
        for(int j=i;j<maxn;j+=i){
            if(!phi[j]) phi[j] =j;
            phi[j] = phi[j]/i*(i-1);
        }
    }
}

long long solve(long long  m){
    long long  sum = 0;
    long long  flag,tmp;
    for(int i=1;i<1ll<<len;i++){
        tmp =1;
        flag =0;
        for(int j=0;j<len;j++){
            if(i&(1ll<<j)){
                tmp *= priD[j];
                flag++;
            }
        }
        if(flag%2)
            sum += m/tmp;
        else
            sum -= m/tmp;
    }
    return sum;
}

int main()
{
    phi_table();
    int t;
    cin>>t;
    long long  n,m;
    while(t--){
        cin>>m>>n;
        if(m>n) //我们先默认 n > m， 不符合交换
            swap(n,m);
        long long sum =0;
        for(int i=1;i<=m;i++)
            sum += phi[i];
        sum = sum*2-1;
        for(int i=m+1;i<=n;i++){
            euler(i);
            sum += (m-solve(m));
        }
        cout<<sum<<endl;
    }
    return 0;
}