Sum to the Target

Given an array of integers nums and an integer target, write a function to find two numbers such that they add up to target and return their indices. You may assume that each input would have exactly one solution, and you may not use the same element twice. Example Input: nums = [2, 7, 11, 15], target = 9 Output: [0, 1] Constraints 2 <= nums.length <= 10^4 -10^9 <= nums[i] <= 10^9 -10^9 <= target <= 10^9 Please provide the algorithm's time complexity. Example Input 4 2 7 11 15 9