Two Sum Pair Finding | Dataford Interview Questions

Affinity solutions uses array-based matching in several product workflows. Given an integer array and a target integer, return every pair of distinct indices whose values sum to the target.

Formal Specification

Implement find_pairs(nums, target). The input nums is a list of integers and target is an integer. Return a list of two-element lists [i, j], where i < j and nums[i] + nums[j] == target. Include all valid index pairs, including pairs formed by duplicate values. The same array element may not be used twice.

Return pairs in increasing order of their second index, and for pairs sharing the same second index, in increasing order of their first index. Return an empty list if no pair exists.

Constraints

0 <= nums.length <= 10^4
-10^9 <= nums[i], target <= 10^9
The output may contain up to O(n²) pairs
Each returned pair must use distinct original indices
Each returned pair must be ordered as [i, j] with i < j

Function Signature

def find_pairs(nums, target):

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