-
Notifications
You must be signed in to change notification settings - Fork 0
/
primes.cpp
51 lines (41 loc) · 1.1 KB
/
primes.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
/**
Sequential implementation of Finding primes.
*/
#include <iostream>
#include <vector>
#include <cmath>
#include <cstdlib>
#include <ff/utils.hpp>
using namespace std;
using ull = unsigned long long;
// see http://en.wikipedia.org/wiki/Primality_test
static bool is_prime(ull n) {
if (n <= 3) return n > 1; // 1 is not prime !
if (n % 2 == 0 || n % 3 == 0) return false;
for (ull i = 5; i * i <= n; i += 6) {
if (n % i == 0 || n % (i + 2) == 0)
return false;
}
return true;
}
int main(int argc, char* argv[]) {
if (argc < 3) {
cerr<<"Usage: "<<argv[0]<<" number1 number2\n";
return -1;
}
ull n1 = std::stoll(argv[1]);
ull n2 = std::stoll(argv[2]);
vector<ull> results;
results.reserve((size_t)(n2-n1)/log(n1));
ff::ffTime(ff::START_TIME);
ull prime;
while((prime=n1++) <= n2)
if (is_prime(prime)) results.push_back(prime);
ff::ffTime(ff::STOP_TIME);
const size_t n = results.size();
cout<<"Found "<<n<<" primes\n";
for(size_t i=0;i<n;++i) cout<<results[i] <<" ";
cout<<"\n\n";
cout<<"Time: "<<ff::ffTime(ff::GET_TIME)<<" (ms)\n";
return 0;
}