【題解】Green Judge g071: F.Lisa 的圍巾

#include <iostream>
using namespace std;
const int maxn = 7005;
bool prime[maxn];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    for (int i = 2; i <= maxn; i++) {
        prime[i] = true;
    }
    prime[0] = false;
    prime[1] = false;
    for (int i = 2; i * i <= maxn; i++) {
        if (prime[i]) {
            for (int j = i + i; j < maxn; j += i) {
                prime[j] = false;
            }
        }
    }
    int T, A, B;
    cin >> T;
    while (T--) {
        cin >> A >> B;
        int sum = 0;
        for (int i = A; i <= B; i++) {
            if (!prime[i]) sum += i;
        }
        cout << sum << "\n";
    }
    return 0;
}