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孪生素数(twinprime)
- @ 2025-12-2 18:40:58
#include<bits/stdc++.h>
using namespace std;
bool a(int b){
if(b<=1)return false;
if(b==2)return true;
if(b%2==0)return false;
for(int i=3;i*i<=b;i+=2){
if(b%i==0)return false;
}
return true;
}
int main(){
int n;
freopen("twinprime.in","r",stdin);
freopen("twinprime.out","w",stdout);
cin>>n;
for(int i=2;i<=n-2;i++){
if(a(i)==true&&a(i+2)==true){
cout<<i<<" "<<i+2<<endl;
}
}
return 0;
}