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 (Clang 3.8.0) (judge verdict: Time Limit Exceeded)

#include <stdio.h>
#include <string.h>
  long n;
  long numbers[7000000];
  long p=0;


int search(long key){
for(long i=0;i<p;i++){
if(numbers[i]==key)return 1;//Found
}

return 0;//Not found
}


int main(void)
{
 
scanf("%ld",&n);

int flg=0;

for(int i=0;i<n;i++){
    long tmp=0;
    scanf("%ld",&tmp);

    if(flg==0){
    if(search(tmp)==0){
        numbers[p]=tmp;
        p++;
    }else{
        flg=1;
    }
    }
}

if(flg==0){
    printf("YES");
}else{
    printf("NO");
}
  return 0;
}