I don't think that this problem needs to exist because it's redundant with the simple array sum challenge. All I did was change sum's type from int to long in Java, and the challenge even told me how.

For people posting their codes, hit enter and tab the first line so it would look coherent.

{
    CODE Like this
}

{ not like

this}

One thing is there is similar "challenge" already, although in this case number may be large, that's fine. It is EASY, but why would you give solver a hint about using specific type? Isn't it a point of a challange to find out for yourself that you need to use type that can hold large number? By revealing this in note, solving it is pointless. And this plagues many of the challenges here. Why give solver all the necessary hints right away is beyond me.

My python 3 solution:

def aVeryBigSum(ar):
    res = 0
    for i in range(len(ar)):
        res += ar[i]
    return res 

Here is Python 3 solution from my HackerrankPractice repository:

n = int(input())
ar = list(map(int, input().split()))
print(sum(ar))

Feel free to ask if you have any questions :)