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)

#define _CRT_SECURE_NO_WARNINGS

#include <stdio.h>

int main(void)
{
	int nums[200000] = {};
	int index = 0;

	scanf("%d", &index);
	if (index > 200000)
	{
		printf("NO\n");
		return 0;
	}

	int tmp = 0;
	for (int i = 0; i < index; i++)
	{
		scanf("%d", &tmp);
		if (tmp > 200000)
		{
			printf("NO\n");
			return 0;
		}
		if (!nums[tmp])
		{
			 nums[tmp] = 1;
		}
		else
		{
			printf("NO\n");
			return 0;
		}
		tmp = 0;
	}
	printf("YES\n");
	return 0;
}