和题解区都不一样的做法，求 Hack 或者证伪。

code:

#include <iostream>
#include <iomanip>
#include <cstdio>
#include <vector>
#include <stack>
#include <queue>
#include <bitset>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <cstring>
#include <sstream>
#include <algorithm>
#include <cmath>
#include <ctime>
#include <cassert>
#include <chrono>
#include <random>
#define x first
#define y second
#define pb push_back
#define eb emplace_back
#define pf push_front
#define desktop "C:\\Users\\incra\\Desktop\\"
#define IOS ios :: sync_with_stdio (false),cin.tie (0),cout.tie (0)
using namespace std;
typedef long long LL;
typedef unsigned long long ULL;
typedef pair <int,int> PII;
const int dx[] = {1,0,-1,0},dy[] = {0,-1,0,1};
template <typename T1,typename T2> bool tomax (T1 &x,T2 y) {
	if (y > x) return x = y,true;
	return false;
}
template <typename T1,typename T2> bool tomin (T1 &x,T2 y) {
	if (y < x) return x = y,true;
	return false;
}
LL power (LL a,LL b,LL p) {
	LL ans = 1;
	while (b) {
		if (b & 1) ans = ans * a % p;
		a = a * a % p;
		b >>= 1;
	}
	return ans;
}
int fastio = (IOS,0);
#define puts(s) cout << s << endl
const int N = 300010,MAX_LOG = 20;
const LL INF = 1e7;
int n;
LL a[N];
int lg[N];
LL f[N][MAX_LOG];
LL gcd (LL a,LL b) {
	return !b ? a : gcd (b,a % b);
}
LL lcm (LL a,LL b) {
	return a / gcd (a,b) * b;
}
LL query (int l,int r) {
	int k = lg[r - l + 1];
	return min (lcm (f[l][k],f[r - (1 << k) + 1][k]),INF);
}
int main () {
//	freopen ("input.in","r",stdin);
	for (int i = 2;i < N;i++) lg[i] = lg[i >> 1] + 1;
	int T;
	cin >> T;
	while (T--) {
		cin >> n;
		for (int i = 1;i <= n;i++) cin >> a[i],f[i][0] = a[i];
		for (int j = 1;j < MAX_LOG;j++) {
			for (int i = 1;i + (1 << j - 1) <= n;i++) f[i][j] = min (lcm (f[i][j - 1],f[i + (1 << j - 1)][j - 1]),INF);
		}
		set <LL> vis;
		for (int i = 1;i <= n;i++) {
			int j = i;
			while (j <= n) {
				if (query (i,j) == INF) break;
				int l = j,r = n;
				while (l < r) {
					int mid = l + r + 1 >> 1;
					if (query (i,j) == query (i,mid)) l = mid;
					else r = mid - 1;
				}
				vis.insert (query (i,j));
				j = l + 1;
			}
		}
		int ans = 1;
		while (vis.count (ans)) ans++;
		cout << ans << endl;
	}
	return 0;
}