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: Wrong Answer)

#include <stdio.h>
#include <string.h>

int main(void)
{
	int n = 0;
	int array[200000];

	if (!(scanf("%d", &n) == 1))
		return (1);
	if (n < 2 || n > 200000)
		return (1);

	int i = 0;
	int j;
	while (i < n - 1 && scanf("%d ", &array[i]) == 1)
	{
		j = 0;
		while (j < i)
		{
			if (j != i && array[j] == array[i])
			{
				printf("NO");
				return (0);
			}
			j++;
		}
		i++;
	}
	printf("YES");
	return (0);
}