Problem

In a One Drop coding screen, implement a function that returns the indices of two numbers in an array whose sum equals a target value.

Given an integer array nums and an integer target, return the indices of the two distinct elements such that nums[i] + nums[j] == target. You may assume exactly one valid answer exists, and you may not use the same element twice.

Formal Specification

• Input:
  • nums: list of integers
  • target: integer
• Output:
  • A list of two integers [i, j] representing the indices of the matching pair

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) <= 10^4
• -10^9 <= nums[i] <= 10^9
• -10^9 <= target <= 10^9
• Exactly one valid answer exists
• The same index cannot be used twice