题解 | #挑7#

#include <stdio.h>
#include <stdbool.h>
bool isContainSeven(int num)
{
    int count = 0;
    while(num>0)
    {
        count = num%10;
        num = num/10;
        if(count == 7)
        {
            return true;
        }
    }
    return false;
}

int main() {
    int n = 0;
    scanf("%d",&n);
    int i = 0;
    int count = 0;
    while(i<n)
    {
        i++;
        if((i%7 == 0) && (!isContainSeven(i)))
        {
            count++;
        }
        if(isContainSeven(i))
        {
            count++;
        }
    }
    printf("%d", count);
    return 0;
}