B. 【例题2】移位包含

解析

判断是否是子串,可以将这个一个环

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

int f = 0;
string a, b;

int main() 
{
    cin >> a >> b;
    for (int i = 0; i < a.size (); ++ i) 
    {
        char c = a[0];  
        a = a.substr (1, a.size() - 1);  
        a = a + c;
        if (a.find (b, 0) != string::npos)
        {  
            cout << "true";
            f = 1;
            break;
        }
    }
    if (!f) cout << "false";
    return 0;
}