1324B.cpp

#include<bits/stdc++.h>
#define ll long long
#define fast ios_base::sync_with_stdio(false);cin.tie(NULL);

#define fi(n) for(ll i=0; i<n; i++)
#define fj(n) for(ll j=0; j<n; j++)
#define fa(n) for(auto i:n)
#define fa2(n) for(auto i:n) cout<<i<<' ';
#define llt ll t; cin>>t; while(t--)

#define vi vector<int>
#define vll vector<ll>
#define vs vector<string>
#define pb push_back
#define pbx ll xx; cin>> xx; v.pb(xx);
#define pbs string xx; cin>> xx; v.pb(xx);
#define all(x) x.begin(), x.end()
#define sortall(x) sort(all(x))
#define rsortall(x) sort(all(x),greater<ll>())

#define gcd(a, b) __gcd(a, b)
#define lcm(a, b) ((a)*((b)/__gcd(a,b)))

#define nl endl
#define endl "\n"
#define yes cout<<"YES"<<endl
#define no cout<<"NO"<<endl
#define C(x) cout<< x <<endl;
#define F i.first
#define S i.second


using namespace std;
int main(){
	llt{
		ll n; cin>>n;
		bool temp=false;
		vll v(n);
		map<ll, ll> m;
		fi(n){
			cin>>v[i];
			if(m.find(v[i]) == m.end()) m[v[i]] = i;
			else{
				if(i-m[v[i]]>1) temp=true;
			}
		}
		if(temp==true) yes;
		else no;
	}
}