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  1. #include <iostream>
  2. #include <vector>
  3. using namespace std;
  4.  
  5. int main() {
  6.     int n;
  7.     cin >> n;
  8.     vector<int> A(n);
  9.     for (int i = 0; i < n; ++i) {
  10.         cin >> A[i];
  11.     }
  12.  
  13.     int peak = 0;
  14.     for (int i = 1; i < n; ++i) {
  15.         if (A[i] > A[peak]) {
  16.             peak = i;
  17.         }
  18.     }
  19.  
  20.     for (int i = 0; i < peak; ++i) {
  21.         if (A[i] >= A[i + 1]) {
  22.             cout << "NO" << endl;
  23.             return 0;
  24.         }
  25.     }
  26.  
  27.     for (int i = peak; i < n - 1; ++i) {
  28.         if (A[i] <= A[i + 1]) {
  29.             cout << "NO" << endl;
  30.             return 0;
  31.         }
  32.     }
  33.  
  34.     cout << "YES" << endl;
  35.     return 0;
  36. }
Success #stdin #stdout 0.01s 5324KB
comments (?)
stdin 
Standard input is empty
stdout 
NO
https://ideone.com/JANH0J
language:
C++14 (gcc 8.3)
created:
9 hours ago
visibility:
public

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