twoSum

[ScoutYin]

Question

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.

Example:

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

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

Solution

const twoSum = function(nums, target) {
  let hash = {};
  for(let i = 0; i < nums.length; i++){
    const j = target - nums[i];
    if(typeof(hash[j]) !== 'undefined'){
      return [hash[j], i];
    }
    hash[nums[i]] = i;
  }
   return [];
};