UVA 10892 LCM Cardinality

题目链接：UVA-10892

题意为给定一个数n，问有多少组不同的数对<a,b>的lcm等于n。看了AC，∑ndless的题解，直接摘抄了。

代码：

#include"cstdio"
#include"iostream"
#include"cstring"
#include"algorithm"
#include"cstdlib"
#include"vector"
#include"set"
using namespace std;
typedef long long LL;
const LL MAXN=1e5;

LL prime[MAXN+1];
void getPrime()
{
    memset(prime,0,sizeof(prime));
    for(LL i=2;i<=MAXN;i++)
    {
        if(!prime[i])prime[++prime[0]]=i;
        for(LL j=1;j<=prime[0]&&prime[j]<=MAXN/i;j++)
        {
            prime[prime[j]*i]=1;
            if(i%prime[j]==0) break;
        }
    }
}

int main()
{
#ifdef LOCAL
    freopen("in.txt","r",stdin);
    //freopen("out.txt","w",stdout);
#endif
    getPrime();
    LL n;
    LL nn;
    while(scanf("%lld",&n)!=EOF && n)
    {
        LL ans=1;
        nn=n;
        for(LL i=1;i<=prime[0];i++)
        {
            LL r=0;
            while(n%prime[i]==0)
            {
                r++;
                n/=prime[i];
            }
            ans*=(2*r+1);
            if(n==1) break;
        }
        if(n>1) ans*=3;
        ans = (ans+1)/2;
        printf("%lld %lld
",nn,ans);
    }
    return 0;
}