Given an unsorted integer array nums and an integer target, return the indices of the two distinct elements whose values add up to target. Exactly one valid answer exists, and you may not use the same element twice.
nums = [2, 7, 11, 15], target = 9Output[0, 1]Why2 + 7 = 9nums = [3, 2, 4], target = 6Output[1, 2]Why2 + 4 = 6`2 <= len(nums) <= 10^5``-10^9 <= nums[i] <= 10^9``-10^9 <= target <= 10^9`Exactly one valid answer exists