hdu 2138 How many prime numbers

How many prime numbers

http://acm.hdu.edu.cn/showproblem.php?pid=2138

Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 19579    Accepted Submission(s): 6696

Problem Description

  Give you a lot of positive integers, just to find out how many prime numbers there are.

 

Input

  There are a lot of cases. In each case, there is an integer N representing the number of integers to find. Each integer won’t exceed 32-bit signed integer, and each of them won’t be less than 2.

 

Output

  For each case, print the number of prime numbers you have found out.

 

Sample Input

3

2

3

4

 

Sample Output

2

 

Author

wangye

 

Source

HDU 2007-11 Programming Contest_WarmUp

 

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Miller_Rabin

测试 15次TLE，5次A了

有谁知道他的时间复杂度吗？

#include<ctime>
#include<cstdio>
#include<cstdlib>
using namespace std;
typedef long long LL;
int n,ans;
LL p;
LL mul(LL a,LL b)
{
    LL r=0;
    while(b)
    {
        if(b&1) b--,r+=a,r%=p;
        a<<=1; a%=p; b>>=1;
    }
    return r;
}
LL qm(LL a,LL b)
{
    LL r=1;
    while(b)
    {
        if(b&1) r=mul(r,a);
        b>>=1; a=mul(a,a);
    }
    return r;
}
bool Miller_Rabin()
{
    if(p==2) return true;
    if(p%2==0) return false;
    int T=5;
    LL m=p-1,k=0,a,x,y;
    while(m%2==0) k++,m>>=1;
    while(T--)
    {
        a=rand()%(p-1)+1;
        x=qm(a,m);
        for(int i=1;i<=k;i++)
        {
            y=mul(x,x);
            if(x&1 && y==1 && x!=1 && x!=-1) return false;
            x=y;
        }
        if(x!=1) return false;
    }
    return true;
}
int main()
{
    srand(time(0));
    while(scanf("%d",&n)!=EOF)
    {
        ans=0; 
        while(n--)
        {
            scanf("%lld",&p);
            if(Miller_Rabin()) ans++;
        }
        printf("%d\n",ans);
    }
}