#include<bits/stdc++.h>
using namespace std;
main()
{
int i,j,k,p,n;
scanf("%d",&n);
int h[n][100],l[n];
for(i=0;i<n;i++)
{
scanf("%d",&l[i]);
for(j=0;j<l[i];j++)
scanf("%d%d",&h[i][j]);
}
for(i=0;i<n;i++)
{
int check=0;
k=l[i]%2;
if(h[i][0]==1&&h[i][l[i]-1]==1&&k==1)
{
k=(l[i]/2);
p=0;
for(j=1;j<=k;j++)
{
int a=h[i][j]-h[i][p];
if(a==1)
{
p++;
}
else
{
check=1;
break;
}
}
if(check==0)
{
p=k+1;
for(j=k;j<l[i]-1;j++)
{
int a=h[i][j]-h[i][p];
if(a==1)
p++;
else
{
check=1;
break;
}
}
}
}
else
{
check=1;
}
if(check==0)
printf("\nyes");
else
printf("\nno");
}
}
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