题解在此

#include <iostream>
#include <cstdio>
using namespace std;
void solve(){
    int n;
    cin>>n;
    int a[2002010];
    for (int i=1;i<=n;i++){
        cin>>a[i];
    }
    int sz1=-1e9,sz2=-1e9;
    for (int i=1;i<=n;i++){
        if (a[i]<sz2){
            cout<<"NO\n";
            return;
        }else if (a[i]<sz1){
            sz2=a[i];
        }else{
            sz1=a[i];
        }
    }
    cout<<"YES\n";
}
int main(){
    int t;
   	cin>>t;
    while (t--){
        solve();
    }
    return 0;
}