Submission

Score: 100

User: peilin

Problemset: Twin, Cousin, and Sexy Prime

Language: c

Time: 0.335 second

Submitted On: 2025-10-12 23:01:54

#include <stdio.h>
#include <stdbool.h>

int main() {
    bool prime[70000002] = {false};
    int l, u;
    scanf("%d %d", &l, &u);

    for (int i = 2; i * i <= u + 6; i++) {
        if (!prime[i]) {
            for (int j = i * i; j <= u + 6; j += i) {
                prime[j] = true;
            }
        }
    }

    int tw = 0, cz = 0, sx = 0;
    for (int i = l; i <= u; i++) {
        if (prime[i]) continue;

        if ((i >= 4 && !prime[i - 2]) || !prime[i + 2]) tw++;
        if ((i >= 6 && !prime[i - 4]) || !prime[i + 4]) cz++;
        if ((i >= 8 && !prime[i - 6]) || !prime[i + 6]) sx++;
    }

    printf("%d\n%d\n%d", tw, cz, sx);
    return 0;
}