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>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
#define int long long int
#define mod 1000000007
#define string_mod 2549536629329_base_255
#define pb push_back
#define F first
#define S second
template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
int power(int x, unsigned int y, int p)
{
    int res = 1;

    x = x % p;
    while (y > 0)
    {

        if (y & 1)
            res = (res * x) % p;

        y = y >> 1;
        x = (x * x) % p;
    }
    return res;
}
int32_t main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    int tc = 1;
    // cin >> tc;
    while (tc--)
    {
        int n;
        cin >> n;
        map<int, int> mp;
        int a[n], f = 0;
        for (int i = 0; i < n;i++){
            cin >> a[i];
            mp[a[i]]++;
            if(mp[a[i]]>1){
                f = 1;
            }
        }
        if(f)
            cout << "YES" << endl;
        else{
            cout << "NO" << endl;
        }
    }

    return 0;
}