#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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