Two Numbers With Target Sum | Dataford Interview Questions

A Wizeline Platform data-processing job receives an unsorted array of integer measurements and a target sum. Return the indices of two distinct elements whose values add up to the target.

Use each array element at most once. Return the indices in ascending order. You may assume every valid input contains exactly one solution.

Formal Specification

Implement two_sum(nums, target):

Input: nums, a list of integers, and target, an integer.
Output: A list containing the two zero-based indices [i, j], where i < j and nums[i] + nums[j] == target.

The solution should efficiently handle large arrays. Consider how a hash map can avoid checking every possible pair.

Constraints

2 <= len(nums) <= 100,000
-10^9 <= nums[i] <= 10^9
-10^9 <= target <= 10^9
Exactly one valid pair exists
The same element cannot be used twice

Function Signature

def two_sum(nums, target):

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