学习<algorithm>下的reverse函数
#include<iostream>
#include<string>
#include<algorithm>
using namespace std;
int n;
bool judge(string s1, string s2, string s3) {
    
 reverse(s1.begin(), s1.end());
 bool flag = true;
 for (int i = 0; i < n; i++)
 {
    
 if (((s2[i] - s1[i]) + (s3[i] - s1[i])) % 26 != 0)
 {
    
 flag = false;
 break;
 }
 }
 return flag;
}
int main()
{
    
 cin >> n;
 string s1, s2, s3;
 cin >> s1 >> s2 >> s3;
 if (judge(s1, s2, s3)) {
    
 reverse(s1.begin(), s1.end()); cout << s1 << endl;
 }
 else if (judge(s2, s1, s3))
 {
    
 reverse(s2.begin(), s2.end()); cout << s2 << endl;
 }
 else if (judge(s3, s2, s1))
 {
    
 reverse(s3.begin(), s3.end()); cout << s3 << endl;
 }
 system("pause");
 return 0;