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 <stdlib.h>

int main()
{
	int i, j, k, n, saida;
	scanf("%d",&n);
	int vetor[n], impostor[n];

	for (i = 0; i < n; i++)
	{
		scanf("%d",&vetor[i]);
		impostor[i] = vetor[i];
	}

	for (j = 0; j < n; j++)
	{
		//printf("V: %d\n",vetor[j]);

		for (k = j + 1; k < n; k++)
		{
			//printf("I: %d\n",impostor[k]);
			if (vetor[j] == vetor[k])
			{
				saida = 1;
				break;
			}
		}
	}

	if (saida != 1)
	{
		printf("YES\n");
	}
	else
	{
		printf("NO\n");
	}

/*	for(int j = 0; j<n; j++)
	{
		printf("%d ",vetor[j]);
	}
*/
	return 0;
}