字典序最小问题Best Cow Line

#include <iostream>#include <string>using namespace std;int main(){    int N = 6;    //cin >> N;    //char s[] = "ACDBCB";    //char s[6] = {'A', 'C', 'D', 'B', 'C', 'B'};    //string s = "ACDBCB";    string s;    cin >> s;    int a = 0;    int b = N - 1;    while(a <= b)    {        bool left = false;        for(int i = 0; a + i <= b; ++i)        {            if(s[a + i] < s[b - i])            {                left = true;                break;            }else if(s[a + i] > s[b - i])            {                left = false;                break;            }        }        if(left)        {            cout << s[a++];        }else        {            cout << s[b--];        }    }    cout << endl;    return 0;}