#include<bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define lowbit(i) (i&-i)
#define rand() (myrand())
using namespace std;
mt19937 myrand(time(0));
const int maxn = 1e5 + 5;
int n, _, nxt[maxn][20], last[maxn], c[maxn], rm[maxn], num[maxn], vis[maxn];
void solve() {
	cin >> n;
	for (int i = 1 ; i <= n ; ++i) {
		rm[i] = 0;
		last[i] = 0;
		nxt[i][0] = n + 1;
		num[i] = 0;
	}
	for (int i = 1 ; i <= n ; ++i) {
		cin >> c[i];
		nxt[last[c[i]]][0] = i;
		last[c[i]] = i;
		num[c[i]]++;
	}
	nxt[n + 1][0] = n + 1;
	for (int j = 1 ; j < 20 ; ++j) {
		for (int i = 1 ; i <= n + 1 ; ++i) nxt[i][j] = nxt[nxt[i][j - 1]][j - 1];
	}
	int ans = 0;
	for (int i = 19 ; i >= 0 ; --i) {
		int cnt = 0;
		for (int j = 1 ; j <= n ; ++j) vis[j] = 0;
		for (int j = n ; j >= 1 ; --j) {
			if (!vis[c[j]] && (num[c[j]]&(1<<i))) cnt++, vis[c[j]] = 1;
		}
		if (cnt == 1 || !cnt || !i) {
			if (cnt) ans |= (1<<i);
			continue;
		}
		int now = n + 1;
		for (int j = n ; j >= 1 ; --j) {
			int pos = j;
			for (int k = i - 1 ; k >= 0 ; --k) pos = nxt[pos][k];
			now = min(now, pos);
			rm[j] = max(rm[j], now);
		}
		now = 0;
		int jud = 0;
		for (int j = 1 ; j <= n ; ++j) vis[j] = 0;
		for (int j = n ; j >= 1 ; --j) {
			if (!vis[c[j]] && (num[c[j]]&(1<<i))) cnt++, vis[c[j]] = 1;
			if (!(num[c[j]]&(1<<i)) || cnt < 2) continue;
			int pos = j;
			for (int k = i - 1 ; k >= 0 ; --k) pos = nxt[pos][k];
			pos--;
			now = max(now, pos);
			if (now >= rm[j]) {
				jud = 1;
				ans |= ((1<<(i + 1)) - 1);
				break;
			}
		}
		if (jud) break;
		ans |= (1<<i);
	}
	cout << ans << '\n';
}
signed main(void) {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin >> _;
	while(_--) solve();
	return 0;
}