Largest prime 尤拉托斯展那筛选法

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.

 

Input

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

 

Output

Output the LPF(n).

 

Sample Input

12345

 

Sample Output

01213

 

<span style="font-family:Arial, Helvetica, sans-serif;"><span style="white-space: normal;">##include<cmath>using namespace std;bool pao(int x){    int i;    if(x==2)    return 1;    for(i=2;i<sqrt(x)+1;i++)    {        if(x%i==0)        return 0;    }    return 1;}int prim[1000005]={0};void init(){    int k;    prim[1]=0; k=1;    for(int i=2;i<1000000;i++)    if(pao(i))    {      for(int j=i; j<1000000; j+=i)        prim[j]=k;        k++;    }}int main(){    int n;    init();    while(scanf("%d",&n)>0)        printf("%d\n",prim[n]);}</span></span>

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