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>

/* void judge(int data[], int n){
    for(int i = 1; i < n; i++){
        for(int j = 0; j < i; j++){
            if(data[i] == data[j]){
                printf("NO\n");
                return ;
            }
        }
    }
    printf("YES\n");
    return ;
}
*/
int main(void){
    int n, judge = 1;
    scanf("%d", &n);
    int data[n];
    for(int i = 0; i < n; i++){
        scanf("%d", &data[i]);
        if(judge == 1){
            for(int j = 0; j < i / 2; j++){
                if(data[i] == data[j] || data[i - j - 1] == data[i]){
                    judge = 0;
                    break;
                }
            }
        }
    }
    if(judge == 1){
        printf("YES\n");
    }else{
        printf("NO\n");
    }
    return 0;
}