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孪生素数
- @ 2025-12-2 19:01:46
#include <bits/stdc++.h>
using namespace std;
long long n;
bool isPrime(int x) {
if (x <= 1) return false;
if (x == 2) return true;
if (x % 2 == 0) return false;
for (int i = 3; i * i <= x; i += 2) {
if (x % i == 0) return false;
}
return true;
}
int main() {
freopen("twinprime.in", "r", stdin) ;
freopen("twinprime.out", "w", stdout) ;
cin >> n;
for (long long i = 2; i <= n - 2; i++) {
if (isPrime(i) && isPrime(i + 2)) {
cout << i << " " << i + 2 << endl;
}
}
return 0;
}