Write a function that, given an array A of N integers, returns the largest integer K > 0 such that both values K and -K exist in

Question

Write a function that, given an array A of N integers, returns the largest integer K > 0 such that both values K and -K exist in array A. If there is no such integer, the function should return 0.
How do I write code for this question?

Answer 1

I would take two sets , append positive to one and -(negative) to other , intersect the both .

After that check if set length is 1 or more or empty and apply max , return 0 or return the only value from set accordingly.

Answer 2

Steps:
1. Take the list A as input
2. Sort the numbers
3. K = 0
4. Let the first positive integer be a candidate for K, if that number satisfies the condition to be K then it'll be our new K
5. Now again select the 2nd positive integer to be a candidate for K and repeat (4)
6. Continue this till the end of the list
7. Return K