hdu2138 How many prime numbers 米勒测试

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 typedef long long ll;
 4 
 5 ll prime[6] = {2,3,5,233,331};
 6 ll qmul(ll a, ll b, ll mod) {
 7     ll res = 0;
 8     while (b) {
 9         if (b&1) res = (res+a)%mod;
10         a = (a+a)%mod;
11         b >>= 1;
12     }
13     return res;
14 }
15 ll qpow(ll a, ll b, ll mod) {
16     ll res = 1;
17     while (b) {
18        if (b&1) res = qmul(res,a,mod);
19        a = qmul(a,a,mod);
20        b >>= 1;
21     }
22     return res;
23 }
24 bool Miller_Rabin(ll p) {
25     if (p < 2) return 0;
26     if (p != 2 && p % 2 == 0) return false;
27     ll s = p-1;
28     while (!(s&1)) s >>= 1;
29     for (int i = 0; i < 5; i++) {
30         if (p == prime[i]) return true;
31         ll t = s, m = qpow(prime[i],s,p);
32         while (t != p-1 && m != 1 && m != p-1) {
33             m = qmul(m,m,p);
34             t <<= 1;
35         }
36         if (m != p-1 && !(t&1)) return false;
37     }
38     return true;
39 }
40 int main() {
41     int n;
42     while (~scanf("%d",&n)) {
43         int ans = 0;
44         for (int i = 1; i <= n; i++) {
45                 ll x; scanf("%lld",&x);
46             if (Miller_Rabin(x)) ans++;
47         }
48         printf("%d\n",ans);
49     }
50     return 0;
51 }