#include<iostream>
#include<cstring>
using namespace std;
int n, t, a[1000005];
int cnt[1000005];
int main()
{
    cin >> t;
    while (t--)
    {
        int l = 1, r = 1, ans = -0x3f3f3f3f;
        bool flag = 1;
        memset(cnt, 0, sizeof(cnt));
        cin >> n;
        for (int i = 1; i <= n; i++)
            cin >> a[i];
        cnt[a[1]] = 1;
        while (l <= r && r <= n)
        {
            if (flag == 1)
            {
                ans = max(ans, r - l + 1);
                r++;
                cnt[a[r]]++;
                if (cnt[a[r]] > 2)
                    flag = 0;
            }
            else
            {
                cnt[a[l]]--;
                if (cnt[a[l]] == 2)
                    flag = 1;
                l++;
            }
        }
        cout << ans << endl;
    }
    return 0;
}