Problem:
Score : 300 points

Problem Statement

Given is a sequence of integers A_1, A_2, ..., A_N.
If its elements are pairwise distinct, print YES; otherwise, print NO.

Constraints

2 ≤ N ≤ 200000

1 ≤ A_i ≤ 10^9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
A_1 ... A_N

Output

If the elements of the sequence are pairwise distinct, print YES; otherwise, print NO.

Sample Input 1

5
2 6 1 4 5

Sample Output 1

YES

The elements are pairwise distinct.

Sample Input 2

6
4 1 3 1 6 2

Sample Output 2

NO

The second and fourth elements are identical.

Sample Input 3

2
10000000 10000000

Sample Output 3

NO

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
  int N;
  cin >> N;
  ll A[N];
  for (int i = 0; i < N; i++) {
    cin >> A[i];
  }
  sort(A,A+N);
  bool ans = true;
  for (int i = 0; i < N - 1; i++) {
    if (A[i] == A[i + 1]) ans = false;
  }
  if (ans) cout << "Yes" << endl;
  else cout << "No" << endl;
  return 0;
}