Identify Number Pairs Adding to Target in Array

##### Scenario Coding round to identify all number pairs that add up to a target in an array containing duplicates. ##### Question Given an integer array (may contain duplicates) and a target sum, return all pairs of values whose sum equals the target, e.g. [1,2,1,0], target=3 -> [(1, 2)]. ##### Hints Use hashmap or sort+two-pointer; account for duplicate counts.