我似乎把题解的太难了

我似乎把题解的太难了

#include<bits/stdc++.h>
using namespace std;

bool isSubstring(const std::string& mainStr, const std::string& subStr) {
    return std::search(mainStr.begin(), mainStr.end(), subStr.begin(), subStr.end()) != mainStr.end();
}
 
int main() {
    std::string str1;
    std::string str2;
    cin >> str2;
    cin >> str1;
    if (isSubstring(str1, str2)) {
        std::cout << str2 << " is substring of " << str1 << std::endl;
    } else {
        std::cout << "No substring";
    }
    return 0;
}