codewars??? Is my friend cheating?

https://www.codewars.com/kata/5547cc7dcad755e480000004/train/java

import java.util.*;
public class RemovedNumbers{
  public static List<long[]> removNb(long n){
    List<long[]> arr = new ArrayList<long[]>();
    long sum = (1+n) * n /2;
    for(long i=n/2+1; i<=n; i++){
      for(long j=n/2+2; j<=n; j++){
        long product = i * j;
        long left = sum - i - j;
        if(i != j){
          if(product == left){
            arr.add(new long[]{i,j});
            arr.add(new long[]{j,i});
            //return arr;
          }
          if(product > left){
            break;
          }
        }
      }
    }
    return arr;
  }
}

Process was terminated. It took longer than 12000ms to complete