Find Two-Sum Key Value | Dataford Interview Questions

Cambridge Mobile Telematics processes numeric signals collected by the DriveWell platform. Given an array of integers and a target value, find the two distinct elements whose values add up to the target.

Return their zero-based indices as a two-element list. Return the indices in increasing order. You may assume that exactly one valid pair exists, and the same array element cannot be used twice.

Formal Specification

Implement two_sum(nums, target):

Input: nums, a list of integers, and target, an integer.
Output: A list [i, j] where i < j and nums[i] + nums[j] == target.

Use a hash map to look up each number's required complement while scanning the array once.

Constraints

2 <= len(nums) <= 100,000
-10^9 <= nums[i] <= 10^9
-10^9 <= target <= 10^9
Exactly one valid pair exists
An element cannot be used more than once

Function Signature

def two_sum(nums, target):

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