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.

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

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

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 indices contain the same value, which is allowed.

Constraints

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