Two Sum

Easy

Problem Description

Given an array of integers `nums` and an integer `target`, return indices of the two numbers in the array such that they add up to `target`. You may assume that each input would have exactly one solution, and you may not use the same element twice. You can return the answer in any order.

Examples

Input: nums = [2,7,11,15], target = 9

Output: [0,1]

Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].

Input: nums = [3,2,4], target = 6

Output: [1,2]

Explanation: Because nums[1] + nums[2] == 6, we return [1, 2].

Input: nums = [3,3], target = 6

Output: [0,1]

Explanation: Because nums[0] + nums[1] == 6, we return [0, 1].

Starter Code

def twoSum(nums: List[int], target: int) -> List[int]:
    # Write your code here
    pass

Hints

  • A really brute force way would be to search for all possible pairs of numbers but that would be too slow.
  • Try to use the fact that the complement of the current number must exist in the array.
  • Could you use extra space to help optimize the search time?