题解

#include<bits/stdc++.h>
using namespace std;
int main(){
    string s_1 ,s_2;
    cin >> s_1 >> s_2;
    if (s_1.find(s_2) != -1)  //如果不包含，find函数会返回-1
        cout << s_2 << " is substring of " << s_1;
    else if (s_2.find(s_1) != -1)
        cout << s_1 << " is substring of " << s_2;
    else
    	cout << "No substring";
    return 0;
}