Submission

Score: 70

User: letdown

Problemset: Twin, Cousin, and Sexy Prime

Language: cpp

Time: 1.095 second

Submitted On: 2025-10-12 11:03:29

#include <iostream>
#include <set>
#include <vector>

using namespace std;

bool isPrime(long long n) {
    if (n < 2) return false;
    for (int i = 2; i*i <= n; i++) {
        if (n % i == 0) return false;
    }
    return true;
}

int main() {
    long long l, u, n;
    cin >> l >> u;
    
    vector<long long> primes;
    for (long long i = l; i <= u; i++) {
        if (isPrime(i)) primes.push_back(i);
    }

    set<long long> tw, cz, sx;
    for (int i = 0; i < primes.size(); i++) {
        if (isPrime(primes[i]+2) || isPrime(primes[i]-2)) tw.insert(primes[i]);
        if (isPrime(primes[i]+4) || isPrime(primes[i]-4)) cz.insert(primes[i]);
        if (isPrime(primes[i]+6) || isPrime(primes[i]-6)) sx.insert(primes[i]);
    }
    cout << tw.size() << "\n" << cz.size() << "\n" << sx.size();
}