#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e6 + 10;

int t, n, ans;
deque<int>q;
unordered_set<int>uset;


int main(){
	cin >> t;
	while(t--){
		q.clear();
		uset.clear();
		ans = 0;
		cin >> n;
		for(int i = 1; i <= n; i++){
			int x;
			cin >> x;
			if(uset.find(x) != uset.end()){
				while(q.size() && q.front() != x){
					uset.erase(q.front());
					q.pop_front();
				}
				uset.erase(x);
				q.pop_front();
			}
			q.push_back(x);
			uset.insert(x);
			ans = max(ans, (int)uset.size());
		}
		cout << ans;
		if(t != 0) cout << endl;
	}
	return 0;
}

最后一行也处理了 求条 真不知道哪里错了