#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long
#define pii pair<int, int>
#define mp(x, y) make_pair(x, y)
const int man = 1e5+10;
class Graph {
public:
    int len, hed[man];
    int ver[man], nxt[man];
    void Ins (int u, int v) {
        ver[++len] = v;
        nxt[len] = hed[u];
        hed[u] = len;
        return ;
    }
    void DIns (int u, int v) {
        Ins(u, v), Ins(v, u);
        return ;
    }
} ;

/*
Windows:
g++ test.cpp -o test.exe
get-content .\test.in | .\test.exe > test.out
*/

int T, n;
int a[man];
int main () {
#ifndef ONLINE_JUDGE
    freopen("test.in", "r", stdin);
    freopen("test.out", "w", stdout);
#endif
    scanf("%d", &T);
    while (T --) {
        bool f = 0;
        scanf("%d", &n);
        for (int i = 1; i <= n; ++ i) scanf("%d", a+i);
        for (int i = 2; i < n; ++ i) {
            if (a[i] == a[1]) {
                for (int j = 1; j <= min(i-2, n-i); ++ j) 
                    if (f = f|(a[1+j] != a[i+j])) break;
                if (f) break;
            }
        } puts(f? "YES" : "NO");
    } return 0;
}

// ---