#include <stdio.h>
#include<iostream>
#include<cstring>
#include<algorithm>
#include<vector>
#define gc getchar_unlocked
using namespace std;
int main() {
iostream::sync_with_stdio(0);
int t;
cin>>t;
while(t--)
{
int n;
cin>>n;
long long int a[n];
for(int i=0;i<n;i++)
{
cin>>a[i];
}
//sort(a,a+n);
int f=0;
for(int i=1;i<n;i++)
{
if(a[i]-a[i-1]>1 || a[i]-a[i-1]<-1) { cout<<"NO"<<endl;
f=1;
break;
}
}
if(f!=1) cout<<"YES"<<endl;
}
return 0;
}
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