此篇属于比赛题解集合(CF && AcWing Race)链接

cf round 853

B

code

#include<iostream>
#include<cstring>

using namespace std;

int solve(int n)
{
    string s;
    cin >> s;


    int cnt = 0;
    for(int i = 0;i < n/2;i ++)
    {
        if(cnt == 0)
           if(s[i] != s[n - i - 1]) cnt ++;

        if(cnt == 1)
          if(s[i] == s[n - i - 1]) cnt ++;

        if(cnt == 2)
         if(s[i] != s[n - i - 1]) cnt ++;

    }


    return cnt;
}

int main()
{
    int t;cin >> t;
    while(t --)
    {
        int n;cin >> n;
        if(solve(n) == 3)cout << "No" << endl;
        else cout << "Yes" << endl;
    }
    return 0;
}