# Unique Integers in array that sum up to zero.

**Objective: **Given an integer N, write a function to return an array containing N unique integers that sum up to zero. There are many possible arrays that sum up to 0 for any N, you need to return any one of such arrays.

**Example:**

N = 4 Output: [-1, 1, -2, 2] or [-1, -2, 3, 0] or [-2, -4, 5, 1] or any other such array that sum to 0. N = 3 Output: [-2, -1, 3] or [-1, 0, 1] or [-2, 0, 2] or any other such array that sum to 0. Note: [2, -1, -1] is not valid output since -1 appears twice sol array elements are not unique.

**Approach:**

As mentioned, there could be more than one correct answer but we need to return any one of those so we will construct the one which is easiest to form-

Include numbers from -N/2 to +N/2 in our result array without 0. Check if N is even or odd. If N is even then does not include 0 in the array and if N is odd then include 0 in the array.

Example if N = 4 then result array would be [-2, -1, 1, -2] where as if N = 5 then result would be [-2, -1, 0, 1, 2].

**Time Complexity:** O(N)

**Complete Code:**

**Output:**

Given N = 4 Constructed Array: [-1, -2, 1, 2], required sum: 0