题解 | #与7无关的数#

//挺常规的一道题
#include "stdio.h"
#include "math.h"
using namespace std;
bool sevenRelated(int x){
    if(x%7 == 0)
        return true;//true为与7相关的数
    while (x > 0){
        if(x%10 == 7)
            return true;
        x = x/10;
    }
    return false;
}

int main(){
    int n;
    while (scanf("%d",&n)!=EOF){
        int sum = 0;
        for (int i = 1; i <= n; ++i) {
            if(!sevenRelated(i))
                sum += pow(i,2);
        }
        printf("%d\n",sum);
    }
}