Pairs With Sum K | Dataford Interview Questions

Luxoft Singapore services may process numeric event attributes where analysts need to identify combinations that reach a specified threshold. Given an integer array and target k, return every unique pair of values whose sum equals k.

Each array element can be used at most once for a pair. If duplicate values produce the same value pair, include that pair only once. Return the result as a list of two-element lists sorted lexicographically, first by the smaller value and then by the larger value. Return an empty list when no pair exists.

Formal Specification

Implement find_pairs(nums, k).

Input: nums, a list of integers, and k, an integer target sum.
Output: a list of unique two-element integer lists [a, b], where a <= b and a + b == k.
A pair may use two equal values only when those values occur at least twice in nums.

Constraints

1 <= len(nums) <= 10^5
-10^9 <= nums[i] <= 10^9
-10^9 <= k <= 10^9
Each output pair contains distinct array occurrences
Duplicate value pairs must be returned only once

Function Signature

def find_pairs(nums, k):

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