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>
#include <string.h>

int main(void) {
//	char s[100];//,t[10],u[10];
	int i=0,j=1;
	int n,a[200000]={0};

	scanf("%d\n",&n);
	while(n!=0){
		scanf("%d",&a[n-1]);
		n--;
	}

	while(a[i]!=0){
		while(a[j]!=0){
			if(a[i]==a[j]){
				printf("No");
				return 0;
			}
			j++;
		}
		i++;
		j=i+1;
	}
	printf("Yes");
	return 0;
}