Two Sum Using Hash Table

Problem

Given an integer array nums and an integer target, return the indices of the two distinct elements whose values add up to target. Return the answer as a list of two indices. You may assume exactly one valid pair exists, and you may not use the same element twice.

Constraints

• 2 <= len(nums) <= 10^5
• -10^9 <= nums[i] <= 10^9
• -10^9 <= target <= 10^9
• Exactly one valid answer exists
• The same array element cannot be used twice