find pair of numbers in array that add to given sum

Question

Question: Given an unsorted array of positive integers, is it possible to find a pair of integers from that array that sum up to a given sum?

Constraints: This shou

Answer 1

The following site gives a simple solution using hashset that sees a number and then searches the hashset for given sum-current number http://www.dsalgo.com/UnsortedTwoSumToK.php