Unique Pairs Sum to Target

EasyPython

Problem

Rakuten Symphony network operations tooling may need to identify distinct combinations of metric values that match a specified threshold. Given an integer array and a target integer, return every unique pair of values whose sum equals the target.

A pair must use two different array positions, but duplicate values should not produce duplicate pairs. Represent each pair as a two-element list in ascending value order. Return pairs in the order they are first discovered during a left-to-right scan. If no pair exists, return an empty list.

Formal Specification

Implement find_unique_pairs(nums, target).

Input: nums, a list of integers, and target, an integer.
Output: A list of two-element lists. Each inner list contains one unique value pair [a, b] where a + b == target and a <= b.
The same array element cannot be used twice in one pair.
Expected average time complexity is O(n).

Constraints

0 <= len(nums) <= 100,000
-10^9 <= nums[i] <= 10^9
-10^9 <= target <= 10^9
Each pair must use two different array positions
Return pairs in first-discovery order

Function Signature

def find_unique_pairs(nums, target):

Formal Specification

Implement find_unique_pairs(nums, target).

Input: nums, a list of integers, and target, an integer.
Output: A list of two-element lists. Each inner list contains one unique value pair [a, b] where a + b == target and a <= b.
The same array element cannot be used twice in one pair.
Expected average time complexity is O(n).