Submission

Score: 100

User: 38408

Problemset: Twin, Cousin, and Sexy Prime

Language: cpp

Time: 0.540 second

Submitted On: 2026-10-13 01:37:13

#include <bits/stdc++.h>
using namespace std;

int countPair(vector<bool>& prime, int l, int u, int diff) {
    int check = 0;

    for (int i = l; i <= u; i++) {
        if (!prime[i]) continue;

        if (prime[i - diff] || prime[i + diff]) {
            check++;
        }
    }

    return check;
}

int main() {
    int l, u;
    cin >> l >> u;

    vector<bool> prime(u + 7, true);
    prime[0] = prime[1] = false;

    for (long long i = 2; i * i <= u + 6; i++) {
        if (prime[i]) {
            for (long long j = i * i; j <= u + 6; j += i) {
                prime[j] = false;
            }
        }
    }

    cout << countPair(prime, l, u, 2) << '\n';
    cout << countPair(prime, l, u, 4) << '\n';
    cout << countPair(prime, l, u, 6) << '\n';

    return 0;
}