LeetCode #1

Given an array of integers, return indices of the two numbers such that they add up to a specific target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.


Given nums = [2, 7, 11, 15], target = 9,

Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].

One loop

  1. loop through the array
  2. store each number’s complement number target - nums[i] in a new array
  3. check the complement array to see if the current number exist


See the Pen 1. Two Sum by Cherry Wang (@chryw) on CodePen.