题解 | #与7无关的数#

#include <iostream>
#include <string>

using namespace std;
bool zhengchu(int n) {//能够整除7的
    if (n % 7 == 0) return true;
    return false;
}
bool baohan(int n) {//包含数字7的
    string str = to_string(n);
    for (int i = 0; i < str.size(); ++i) {
        if (str[i] == '7') return true;
    }
    return false;
}
int main() {
    int n;
    while (cin >> n) {
        int sum = 0;
        for (int i = 1; i <= n ; ++i) {
            if (!zhengchu(i) && !baohan(i)) {
                sum += i * i;
            }
        }
        cout << sum << endl;
    }
}