题解

#include<bits/stdc++.h>
using namespace std;
string s1,s2;
int main(){
     cin>>s1>>s2;
    if(s1.find(s2)!=string::npos)cout<<s2<<" is substring of "<<s1;
    else if(s2.find(s1)!=string::npos)cout<<s1<<" is substring of "<<s2;
    else cout<<"No substring";
    return 0;
}