#include <iostream>
#include <algorithm>
using namespace std;

int main()
{
    string s1, s2;
    cin >> s1 >> s2;
    if (s1.size() < s2.size()) swap (s1, s2);
    for (int i = 0; i < s1.size(); i ++ )
    {
        s1 = s1.substr(1) + s1[0];
        for (int j = 0; j + s2.size() <= s1.size(); j ++ )
            for (int k = 0; k <= s2.size(); k++ )
            {
                if (s1[j + k] != s2[k]) 
                break;
                if (k == s2.size())
                {
                    puts ("true");
                    return 0;
                }
            }
    }
    puts ("false");

    return 0;
}

第二种简洁写法(自己写的)

#include <iostream>
#include <algorithm>

using namespace std;

int main()
{
    string a, b;
    cin >> a >> b;

    if (a.size() < b.size()) swap(a, b);
    for (int i = 0; a[i]; i ++ )
    {    
        a = a.substr(1) + a[0];//循环位移操作

        for (int j = 0; j + b.size() <= a.size(); j ++ )
        {
            int k = 0;
            while (k < b.size() && a[j + k] == b[k]) k ++ ;

            if (k == b.size()) 
            {
                cout << "true" << endl;
                return 0;
            }
        }
    }

    puts("false");

    return 0;
}