#include <bits/stdc++.h>

 using namespace std;

 set<int> Set;

 const int maxn =  + ;

 int a[maxn];

 int Scan() {    //输入外挂

     int res = ;

     char ch;

     while((ch = getchar()) >= '' && ch <= '')

         res = res *  + (ch - '');

     return res;

 }

 int main()

 {

     //freopen("in.txt", "r", stdin);

     int T, n;

     scanf("%d", &T);

     while(T--)

     {

         Set.clear();

         scanf("%d", &n); getchar();

         for(int i = ; i < n; ++i) a[i] = Scan();

         int L = , R = , ans = ;

         for(; L < n; ++L)

         {

             while(R < n &&!Set.count(a[R])) { Set.insert(a[R]); R++; }

             ans = max(ans, R - L);

             if(R == n) break;

             Set.erase(a[L]);

         }

         printf("%d\n", ans);

     }

     return ;

 }