#include <bits/stdc++.h>
#define fast ios::sync_with_stdio(false)
#define ct cin.tie(nullptr)
#define ll long long
#define nl '\n'
#define newline cout<<'\n'
#define yes cout<<"YES"<<'\n'
#define no cout<<"NO"<<'\n'
using namespace std;
void solve()
{


}
int main()
{
    fast;
    ct;
    int t;
    cin>>t;
    while(t--)
    {
        int n;
        cin>>n;
        vector<int>arr(n);
        for(auto& x: arr)
            cin>>x;
        bool ms = false;
        for(int i=0; i+1<n; i++)
        {
            if(abs(arr[i]-arr[i+1])==1)
               ms=true;
            else
            {
                ms=false;
            }
        }
        if(ms)
            yes;
        else
            no;
    }
}