#include<iostream>
#include<algorithm>
using namespace std;
int main()
{
int t;
cin>>t;
while(t--)
{
int n;cin>>n;
int jimin=999999999,oumax=0;
for(int i=1;i<=n;i++)
{
int x;cin>>x;
if(i%2==1)jimin=min(jimin,x);
else oumax=max(oumax,x);
}
if(n%2==0&&jimin-oumax>=2)cout<<"YES"<<endl;
else cout<<"NO"<<endl;
}
return 0;
}