我这为啥错啊？调好久没调出

#include<bits/stdc++.h>
using namespace std;
string s;
int T;
bool YN=false;
int main(){
	cin>>T;
	for(int i=0;i<T;i++){
		cin>>s;
		for(int j=16;j>3;j--){
			if(s[j-3]==s[j-2]&&s[j-2]==s[j-1]&&s[j-1]==s[j]){
				cout<<"YES";
				YN=true;
				break;
			}
			if(s[j]=='D'&&s[j-1]=='X'){
				cout<<"YES";
				YN=true;
				break;
			}
		}
		if(YN==false){
			cout<<"NO";
		}
	}
    return 0;
}