题解

#include <iostream>
#include <cmath>
#include <string>
#include <cstring>
#include <iomanip>
#include <algorithm>
#include <vector>
#include <cstdio>
using namespace std;
const int N=1,inf=2147483647;
int T,n,m,cnt;
string s;
int main(){
	cin>>T;
	while(T--){
		cin>>n;
		cin>>s;
		s="2"+s+"2";
		m=n/2;
		cnt=0;
		for(int i=1;i<=m;i++){
			if(s[i]!=s[n-i+1]&&s[i-1]==s[n-i+2])cnt++;	
		}
		if(cnt>=2)cout<<"NO\n";
		else cout<<"YES\n";
	}
	return 0;
}