【題目敘述】https://zerojudge.tw/ShowProblem?problemid=d362
#include <iostream>
#include <vector>
using namespace std;
const int maxn = 20000000;
bool prime[maxn]; // 用 int 會 MLE
vector<int> v;
int main() {
// 建立質數表
for (int i=2; i<maxn; i++)
prime[i] = 1;
int p = 2;
while (p*p < maxn){
if (prime[p] == 1)
for (int i=p*p; i<maxn; i+=p){
prime[i] = 0;
}
p++;
}
// 找出符合題意的質數
for (int i=2; i<maxn-2; i++){
if (prime[i] && prime[i+2])
v.push_back(i);
}
int S;
while (cin >> S)
cout << '(' << v[S-1] << ", " << v[S-1]+2 << ")\n";
return 0;
}