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 (Clang 3.8.0) (judge verdict: Wrong Answer)

#include <stdio.h>

int main()
{
  int input;
  int i;
  int array[200000];
  scanf("%d", &input);
  for(i = 0; i < input; ++i)
    scanf("%d", &array[i]);
  int j;
  int judge = 0;
  for(i = 0; i < input; ++i){
    for(j = input - i; j < input; ++j){
      if((array[i] ^ array[j]) && (i ^ j)){
        judge = 1;
      }
    }

  }
  if(judge == 0)
    printf("YES\n");
  else
    printf("NO\n");
  return 0;
}