HDU 2136 largest prime factor

<code>

#include<stdio.h>
__int64 n;
__int64 prime[1000000];
int main()
{
    __int64 i,j;
    __int64 locate=0;
    for(i=2;i<1000000;i++)
    {
        if(prime[i]==0)
        {
            locate++;
            for(j=i;j<1000000;j+=i)
            {
                prime[j]=locate;
            }
        }
    }
    while(scanf("%I64d",&n)!=EOF)
    {
        printf("%I64d\n",prime[n]);
    }
    return 0;
}
</code>