Problem

In a Google embedded systems context, you may need to scan a small telemetry buffer and quickly identify two readings whose sum matches a target calibration value. Given an integer array nums and an integer target, return the indices of the two distinct elements whose values add up to target.

You may assume there is exactly one valid answer, and you may not use the same element twice.

Formal Specification

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

Examples

Example 1

• Input: nums = [2, 7, 11, 15], target = 9
• Output: [0, 1]
• Explanation: nums[0] + nums[1] = 2 + 7 = 9

Example 2

• Input: nums = [3, 2, 4], target = 6
• Output: [1, 2]
• Explanation: nums[1] + nums[2] = 2 + 4 = 6

Constraints

• 2 <= len(nums) <= 10^5
• -10^9 <= nums[i] <= 10^9
• -10^9 <= target <= 10^9
• Exactly one valid answer exists
• Return indices in the order they are found by the algorithm