Problem 1

Wording

Given a list of numbers and a number k, return whether any two numbers from the list add up to k.

For example, given [10, 15, 3, 7] and k of 17, return true since 10 + 7 is 17.

Bonus: Can you do this in one pass?

Process followed to solve the problem

First thoughts were to nest for loops, that way you could have the first number and then check the others, but I knew this was overkilled. So I came up with realizing that if your k was substracted a number from the array you would just need to look for a number that is equals to the result of that substraction.

Solution

function findPair(numbers, k) {
  for (let number of numbers) {
    if ((foundIndex = numbers.indexOf(k - number)) !== -1) {
      return [number, numbers[foundIndex]];
    }
  }
}