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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. #define fast_io ios::sync_with_stdio(0); cin.tie(0); cout.tie(0)
  5. #define int long long
  6. #define rep(i,a,b) for(int i=a;i<b;++i)
  7. #define yes cout << "YES\n"
  8. #define no cout << "NO\n"
  9.  
  10. void solve() {
  11. int n; cin >> n;
  12. int* a = new int[n];
  13. rep(i,0,n) cin >> a[i];
  14.  
  15. int peak = 0;
  16. while (peak + 1 < n && a[peak] <= a[peak + 1]) ++peak;
  17. while (peak + 1 < n && a[peak] >= a[peak + 1]) ++peak;
  18.  
  19. (peak == n - 1 ? yes : no);
  20.  
  21. delete[] a;
  22. }
  23.  
  24. int32_t main() {
  25. fast_io;
  26. int t; cin >> t;
  27. while (t--) solve();
  28. return 0;
  29. }
  30.  
Success #stdin #stdout 0.01s 5312KB
stdin
4
4
5 6 1 1
3
3 1 2
3
40 60 90
2
1 1
stdout
YES
NO
YES
YES