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 Java (OpenJDK 11.0.6) (judge verdict: Wrong Answer)

import java .util.ArrayList;
import java.util.Collections;
import java .util.Scanner;
public class Main {
public static void main(String[] args) {
	Scanner sc = new Scanner(System.in);

	ArrayList<Integer> inA = new ArrayList<>();

	int inputN = sc.nextInt();
	Boolean boo = true;

	for(int i = 0; i < inputN; i++) {
		inA.add(sc.nextInt());
	}

	Collections.sort(inA, Collections.reverseOrder());

	for(int i = 0; i < inputN-1; i++) {
		int n = inA.get(i);
			if(n == inA.get(i + 1)) {
				boo = false;
				break;

		}

	}

	if(boo == true) {
		System.out.println("Yes");
	}else {
		System.out.println("No");
	}

}
}