hdu2136 ----Largest prime factor

Largest prime factor

Time Limit: 5000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)

Total Submission(s): 13740    Accepted Submission(s): 4852

Problem Description

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

 

模板题

#include<iostream>#include<cmath>#include<cstring>#include<vector>#include<stdlib.h>#include<stdio.h>#include<algorithm>#include<map>#include <set>#include <list>#include <deque>#include<sstream>#include<time.h>#define pi  3.1415926using namespace std;typedef long long ll;const int maxn = 1000000 + 5;const int day =21252;const int mod=1000000007;const ll N=1000000;ll prime[N]={0},num_prime=0;ll isnotprime[N]={1,1};void kuai(){    memset(prime,0,sizeof(prime));    ll t=1;    for(int i=2;i<N;i++)    {        if(!prime[i])        {            for(int j=i;j<N;j+=i)            {                prime[j]=t;            }            t++;        }    }}int main(){    ll n;    kuai();    while(~scanf("%lld",&n))    {        if(n==1)            cout<<"0"<<endl;        else        cout<<prime[n]<<endl;    }    return 0;}