Problem Statement

At Stripe, you are 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] such that nums[i] + nums[j] == target and i != j
• The returned indices may be in any order.

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

Example 3

• Input: nums = [3, 3], target = 6
• Output: [0, 1]
• Explanation: The two different positions contain the required values.

Constraints

• 2 <= len(nums) <= 10^5
• -10^9 <= nums[i] <= 10^9
• -10^9 <= target <= 10^9
• Exactly one valid answer exists