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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>

using namespace std;

int main() {
    int n;
    cin >> n;
    map<long long, int> m;
    bool ans = false;
    for(int i = 0; i < n; i++) {
        long long a;
        cin >> a;
        try {
            m.at(a)++;
            ans = true;
            break;
        } catch (out_of_range) {
            m.insert(make_pair(a, 1));
        }
    }
    if (ans) cout << "Yes" << endl;
    else cout << "No" << endl;
    return 0;
}