#include<iostream>
#include<vector>
#include<algorithm>
#include<cstring>
//#define int ll
#define lc (rt<<1)
#define rc (rt<<1|1)
#define mid (l+r>>1)
#define rg register
#define pb push_back
#define ppb pop_back
#define mkp make_pair
#define prq_mn(x) priority_queue<x, vector<x>, greater<x> >
#define prq_mx(x) priority_queue<x, vector<x>, less<x> >
#define Clear(x, y) memset(x, y, (n+10)*sizeof(int))
#define fi first
#define se second
#define DEBUG printf("Debug on line %d\n", __LINE__)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
const int N = 2e5 + 114514;
const int INF = 0x3f3f3f3f;
const int inf = 0xcfcfcfcf;

template <typename T> bool updmax(T& a, T b) {return a<b ? a=b, 1 : 0;}
template <typename T> bool updmin(T& a, T b) {return a>b ? a=b, 1 : 0;}

inline int read(){
	int n=0, f=1; char ch = getchar();
	for(; !isdigit(ch); ch=getchar()) if(ch == '-') f=-1;
	for(; isdigit(ch); ch=getchar()) n=n*10+ch-'0';
	return n*f;
}

int T;
int n, m;
int a[N];
vector<int> vec; 
int mx[N], mxk[N], smx[N], smxk[N];
int lst[N], tp;

void addlst(int x){
	for(int i=tp; i>=0; i--){
		if(lst[i] == x){ // 找到相同的 
			for(int j=i; j<tp; j++) lst[j] = lst[j+1];
			lst[tp] = x;
			return;
		}
	}
	
	// 没找到相同的 
	lst[++tp] = x;
} 

void upd1(int y, int val, int k){
//	printf("upd1(%d, %d, %d, %d, %d)\n", x, y, val, k);
	if(val > mx[y]){
		smx[y] = mx[y];
		smxk[y] = mxk[y];
		mx[y] = val;
		mxk[y] = k;
	} else if(k != mxk[y] && val > smx[y]){
		smx[y] = val;
		smxk[y] = k;
	}
}

void upd(int y1, int y2, int val, int ii){
//	printf("upd(%d, %d, %d, %d, %d, %d)\n", x1, y1, x2, y2, val, ii);
	if(!val || mxk[y2] != a[ii]) upd1(y1, mx[y2]+val, val ? y2 : mxk[y2]);
	if(!val || smxk[y2] != a[ii]) upd1(y1, smx[y2]+val, val ? y2 : smxk[y2]);
}

signed main(){
	T = read();
	while(T--){
		vec.clear();
		
		n = read();
		for(int i=1; i<=n; i++){
			a[i] = read();
			vec.pb(a[i]);
		}
		
		sort(vec.begin(), vec.end());
		vec.erase(unique(vec.begin(), vec.end()), vec.end());
		m = vec.size();
		for(int i=1; i<=n; i++){
			a[i] = lower_bound(vec.begin(), vec.end(), a[i]) - vec.begin() + 1;
//			printf("a[%d] = %d\n", i, a[i]);
		}
		
		Clear(mx, inf); Clear(mxk, inf); Clear(smx, inf); Clear(smxk, inf);
		Clear(lst, 0);
		tp = 0;
		mx[0] = 0; mxk[0] = 0;
		for(int i=1; i<=n; i++){
			for(int jj=tp; jj>=0; jj--){
				int j = a[jj];
				if(a[i] != j) upd(a[i], j, 1, i);
			}
			addlst(a[i]);
			
//			for(int j=0; j<=m; j++){
//				printf("mx[%d][%d] = %d\n", i, j, mx[j]);
//				printf("mxk[%d][%d] = %d\n", i, j, mxk[j]);
//				printf("smx[%d][%d] = %d\n", i, j, smx[j]);
//				printf("smxk[%d][%d] = %d\n", i, j, smxk[j]);
//			}
		}
		
		int ans = inf;
		for(int j=0; j<=m; j++){
			ans = max(ans, mx[j]);
		}
		printf("%d\n", ans);
	}
}