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.


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.


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:


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

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If you find anything incorrect or you feel that there is any better approach to solve the above problem, please write comment.

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