帮我举个反例也行 谢谢！

#include<iostream>
#include<algorithm>
using namespace std;
int main()
{
	string str, s = "", str1;
	cin >> str;
	str1 = str;
	for ( int i = 0; i < str.size(); i++)
	{
		for (int j = i + 1; j < str.size(); j++)
		{
			string x = str.substr(0, i);
			string y = str.substr(i, j - i + 1);
			string z = str.substr(j + 1);
			for (int k = 0; k < 3; k++)
			{
				if (k == 0)
				{
					reverse(x.begin(), x.end());
					s = x + y + z;
					str1 = min(s, str1);
				}
				else if (k == 1)
				{
					reverse(y.begin(), y.end());
					s = x + y + z;
					str1 = min(s, str1);
				}
				else
				{
					reverse(z.begin(), z.end());
					s = x + y + z;
					str1 = min(s, str1);
				}


			}
		}
	}
	cout << str1;
}