hdoj Largest prime factor

Everybody knows any number can be combined by the prime number.
Now, your task is telling me what position of the largest prime factor.
The position of prime 2 is 1, prime 3 is 2, and prime 5 is 3, etc.
Specially, LPF(1) = 0.

Each line will contain one integer n(0 < n < 1000000).

Output the LPF(n).

1
2
3
4
5

0
1
2
1
3

#include<cstdio>
#include<cstdlib>
#include<cstring>
#define maxn 1000000+5
using namespace std;
int isprime[maxn],a[maxn];
void countprime(){
			int i,j,e=0;
			for(i=2;i*i<maxn;++i){
				if(isprime[i])continue;
				for(j=i*i;j<maxn;j+=i)
				isprime[j]=1;
			}
}
void   que(){
		int i,j=1,e=1;
		a[1]=0;
		for(i=2;i<=maxn;++i){
			if(!isprime[i]){
			for(j=i;j<maxn;j+=i){
				if(j%i==0&&j/i>i&&!isprime[j/i]);//房超时
				else a[j]=e;
			}
			e=e+1;
			}
		}
}
int main()
{
	countprime();
	que();
	int i,j,n;
	while(scanf("%d",&n)!=EOF){
		printf("%d\n",a[n]);
	}
	return 0;
}