#include <bits/stdc++.h>
#define nmx 2005
#define sqr 317
using namespace std;
int t,n,x;
int main()
{
    ifstream f ("nivele.in");
    ofstream g ("nivele.out");
    f>>t;
    while (t--)
    {
        f>>n;
        deque <int> dq;
        for (int i=1; i<=n; i++)
        {
            f>>x;
            if (dq.empty())
                dq.push_back(x);
            else
            {
                while (dq.front()==x)
                {
                    dq.pop_front();
                    x--;
                }
                dq.push_front(x);
            }
        }
        if (dq.size()==1 && dq.front()==1)
            g<<"DA"<<'\n';
        else g<<"NO"<<'\n';
    }
}