virtual hust 2013.6.21 数论基础题目 H - Factoring Large Numbers

#include <cstdio>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <cstring>
using namespace std;
#define maxn 1000001
bool vis[maxn];
int prime[maxn];
int n_prime=0;
void Prime()
{
memset(vis,true,sizeof(vis));
vis[1]=vis[0]=false;
for(int i=2;i<maxn;i++)
{
if(vis[i])
{
prime[++n_prime]=i;
for(int j=2*i;j<maxn;j+=i)
vis[j]=false;
}

}
//cout<<n_prime<<" "<<prime[n_prime]<<endl;
}
int main()
{
Prime();
long long n;
while(scanf("%lld",&n)!=EOF)
{
if(n<=0)
break;
for(int i=1;i<=n_prime;i++)
{
if(n%prime[i]==0)
{
while(n%prime[i]==0)
{
printf("    ");
printf("%d\n",prime[i]);
n/=prime[i];
}
}
}
if(n!=1)
printf("    %lld\n",n);
printf("\n");
}
return 0;
}