Submission

Score: 100

User: patsa_v

Problemset: Twin, Cousin, and Sexy Prime

Language: cpp

Time: 0.432 second

Submitted On: 2025-10-15 12:06:22

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

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int l,r;
    cin >> l >> r;
    vector<bool> sieve(r+10,true);
    sieve[0] = sieve[1] = false;

    for(int i = 2;i<=r+6;i++){
        if(!sieve[i]) continue;
        for(int j = i*2;j<=r+6;j+=i){
            sieve[j] = false; 
        }
    }

    int a1 = 0, a2 = 0, a3 = 0;
    // 3 <= l < r <= 70,000,000
    for(int i = l;i<=r;i++){
        if(!sieve[i]) continue;
        if((i >= 5 && sieve[i-2]) || sieve[i+2]) a1++;
        if((i >= 7 && sieve[i-4]) || sieve[i+4]) a2++;
        if((i >= 9 && sieve[i-6]) || sieve[i+6]) a3++;
    }

    cout << a1 << '\n' << a2 << '\n' << a3 ;
    return 0;
}