#include<cstdio>
#include<algorithm>
#include<set>
#define LL long long

using namespace std;
int N;
int in[50010];
long long hash[50010];
LL base=31;
long long modulo=9223372036854775807;


bool step(int k)
{
	set<LL> sset;
	if(k==1)
	{
		for(int i=0;i<N;i++)
		{
			if(sset.find(in[i])!=sset.end()) return false;
			sset.insert(in[i]);

		}
		return true;
	}


	//init hash
	LL ihash=0;
	LL d=base;
	for(int i=0;i<k;i++)
	{
		ihash=(base) * (ihash) + in[i];
		ihash=ihash%modulo;
		if(i<k-2) d=d*base;
		d=d%modulo;
	}
	hash[0]=ihash;
	sset.insert(ihash);
	//printf("i=%lld d %lld\n",ihash,d);

	for(int i=1;i<=N-k;i++)
	{

		hash[i]=hash[i-1]-d*in[i-1];
		hash[i]=hash[i]*base;
		hash[i]=hash[i]+in[i+k-1];
		//printf("H[%d]=%lld\n",i,hash[i]);
		if(sset.find(hash[i])!=sset.end()) return false;
		sset.insert(hash[i]);
	}
	return true;
}

int main()
{
	int Z;
	scanf("%d",&Z);
	while(Z--)
	{
		scanf("%d",&N);
		for(int i=0;i<N;i++)
		scanf("%d",&in[i]);

	/*	for(int i=0;i<N;i++)
		{
			printf("step(%d)=%d\n",i,step(i));

		}*/

		int p=0, q=N,s;
		while(p!=q)
		{

			s=(p+q+1)/2;
			//printf("%d\n",s);
			if(step(s))
			q=s-1;
			else
			p=s;







		}
		if(s==N) printf("%d\n",N); else
		printf("%d\n",s+1);
	}

	return 0;
}