题解 | 与7无关的数

#include<bits/stdc++.h>
using namespace std;

bool about7(int k)
{
    int result = k;
    int num = 0;
    while(result!=0)
    {
        num = result % 10;
        result /= 10;
        if(k%7 == 0||num == 7)
        {
            return true;
        }
    }
    return false;
}

int main()
{
    int n;
    while(cin>>n)
    {
        int sum = 0;
        for(int i = 1;i<=n;i++)
        {
            if(!about7(i))
            {
                sum += pow(i,2);
            }
        }
        cout<<sum<<endl;
    }

    return 0;
}