暴力求解
#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
int n, k, res;
int main()
{
cin >> n >> k;
for (int i = 1; i <= n; i ++ )
{
string s = to_string(i);
for (int j = 0; j < s.size(); j ++ )
if (s[j] == k + '0') res ++ ;
}
cout << res << endl;
return 0;
}