Two-Sum in an Array | Dataford Interview Questions

A PlayStation Network service receives an array of integer event values and a target integer k. Determine whether two distinct elements in the array sum exactly to k. The same array element cannot be used twice, but duplicate values at different indices may form a valid pair.

Return True if such a pair exists, otherwise return False.

Formal Specification

Implement has_pair_sum(nums, k).

Input: nums, a list of integers, and k, an integer target.
Output: A Boolean indicating whether two different indices i and j satisfy nums[i] + nums[j] == k.
The order of the pair does not matter.
The input array must not be modified.

Constraints

2 <= len(nums) <= 100,000
-10^9 <= nums[i] <= 10^9
-2 * 10^9 <= k <= 2 * 10^9
The input array may contain duplicates and negative values
The input array must not be modified

Function Signature

def has_pair_sum(nums, k):

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