#include<iostream>  #include<set>using namespace std;const int maxn = 1000000 + 5;int a[maxn];int n;int maxd;void solve(){    set<int> num;    int L = 0, R = 0;    maxd = 0;    int ans = 0;    while (R < n)    {        if (!num.count(a[R]))        {            ans++;            num.insert(a[R]);            R++;            if (ans>maxd)  maxd = ans;        }        else        {            num.erase(a[L]);            ans--;            L++;        }    }}int main(){    //freopen("D:\\txt.txt", "r", stdin);    int t;    cin >> t;    while (t--)    {        cin >> n;        for (int i = 0; i < n; i++)        {            cin >> a[i];        }        solve();        cout << maxd << endl;    }    return 0;}