题解 | 与7无关的数

#include <iostream>
using namespace std;
bool sevenRelated(int n){
    if(n%7==0) return true;
    int revx = 0;
    while(n!=0){
        revx = n%10;
        if(revx == 7) return true;
        n /= 10;
    }
    return false;
}//判断一个数是否和7有关

int main() {
    int n;
    cin >> n;
    int sum = 0;
    for(int i = 1; i <= n; i++){
        if(sevenRelated(i)) continue;//如果和7有关，跳过此次循环
        else sum += i*i;
    }
    cout<<sum<<endl;
}