#include<iostream>

 #include<cstdio>

 #include<cstring>

 #include <cmath>

 #include<stack>

 #include<vector>

 #include<map>

 #include<set>

 #include<queue>

 #include<algorithm>

 #define mod=1e9+7;

 using namespace std;

 typedef long long LL;

 const int maxn=+;

 int a[maxn];

 int main(){

     int t,n;

     scanf("%d",&t);

     while(t--){

         scanf("%d",&n);

         for(int i=;i<n;i++) scanf("%d",&a[i]);

         set<int> s;

         int l=,r=,ans=;

         while(r<n){

             while(r<n&&!s.count(a[r])) s.insert(a[r++]);

             ans=max(ans,r-l);

             s.erase(a[l++]);

         }

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

     }

     return ;

 }