#include<iostream>
#include<algorithm>
#include<cstring>
#include<stack>
#include<vector>
using namespace std;
int main()
{
    string s1,s2;
    cin>>s1>>s2;
    int p=s1.find(s2);
    int pos=s2.find(s1);
    if(p!=-1)
        cout<<s2<<" is substring of "<<s1;
    if(pos!=-1)
        cout<<s1<<" is substring of "<<s2;
    if(p==-1&&pos==-1)
        cout<<"No substring";
    return 0;
}

为什么有一个用例过不去啊?求大佬指点