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: Runtime Error)

#include <stdio.h>
#include <stdlib.h>

int main(){
  int N;
  long int *A;
  long int *table;
  int i=0;
  int flag = 0;
  long int tmp;
  
  scanf("%d",&N);
  
  A = (long int *)malloc(sizeof(long int) *N);
  table = (long int *)malloc(sizeof(long int) *100000000);
  
  for(i=0;i<N;i++){
  
    scanf("%ld",&A[i]);
    tmp = A[i];
    if(table[tmp] != 1) table[tmp] = 1;
    else if(table[tmp] == 1){
      flag = 1;
      break;
    }
  }
  
  if(flag) printf("NO\n");
  else printf("YES\n");
  
  free(A);
  free(table);
  return 0;
}