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 (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
  int N, i, j, tmp;
  int judge = 0;
  int A[200001];
  
  scanf("%d", &N);
  scanf("%d", &A[0]);
  for (i = 1; i < N; i++)
  {
    scanf("%d", &A[i]);
    for (j = i; j > 0; j--)
    {
      if (A[j] < A[j-1])
      {
        tmp = A[j-1];
        A[j-1] = A[j];
        A[j] = tmp;
      }
      else
      {
        break;
      }
    }
    if (A[j] == A[j-1])
    {
      judge = 1;
      break;
    }
  }
  
  if (judge == 0)
  {
    printf("YES\n");
  }
  else
  {
    printf("NO\n");
  }
  
  return 0;
}