Technical test

The goal of these exercises is to allow a reflexion about choosen solutions and to discuss between us during the technical interview. There is not only ONE correct solution.

First exercise : Binary chop

A binary chop (sometimes called the more prosaic binary search) finds the position of value in a sorted array of values. It achieves some efficiency by halving the number of items under consideration each time it probes the values: in the first pass it determines whether the required value is in the top or the bottom half of the list of values. In the second pass in considers only this half, again dividing it in to two. It stops when it finds the value it is looking for, or when it runs out of array to search. -- http://codekata.com/kata/kata02-karate-chop/

Write a binary search function that takes an integer search target and a sorted array of integers. It should return the integer index of the target in the array, or -1 if the target is not in the array.

The signature will logically be:

binaryChop(int, array_of_int)  -> int

Here is the Test::Unit code. The tests assume that array indices start at zero. You’ll probably have to do a couple of global search-and-replaces to make this compile in your language of choice (unless your enlightened choice happens to be Ruby).

def test_knpFunction
  assert_equal(-1, knpFunction(3, []))
  assert_equal(-1, knpFunction(3, [1]))
  assert_equal(0,  knpFunction(1, [1]))
  #
  assert_equal(0,  knpFunction(1, [1, 3, 5]))
  assert_equal(1,  knpFunction(3, [1, 3, 5]))
  assert_equal(2,  knpFunction(5, [1, 3, 5]))
  assert_equal(-1, knpFunction(0, [1, 3, 5]))
  assert_equal(-1, knpFunction(2, [1, 3, 5]))
  assert_equal(-1, knpFunction(4, [1, 3, 5]))
  assert_equal(-1, knpFunction(6, [1, 3, 5]))
  #
  assert_equal(0,  knpFunction(1, [1, 3, 5, 7]))
  assert_equal(1,  knpFunction(3, [1, 3, 5, 7]))
  assert_equal(2,  knpFunction(5, [1, 3, 5, 7]))
  assert_equal(3,  knpFunction(7, [1, 3, 5, 7]))
  assert_equal(-1, knpFunction(0, [1, 3, 5, 7]))
  assert_equal(-1, knpFunction(2, [1, 3, 5, 7]))
  assert_equal(-1, knpFunction(4, [1, 3, 5, 7]))
  assert_equal(-1, knpFunction(6, [1, 3, 5, 7]))
  assert_equal(-1, knpFunction(8, [1, 3, 5, 7]))
end

Second exercise

Write unit tests you seem necessary for this particular function :

  const italianGuy = (number) => {
    let n1 = 0
    let n2 = 1
    let sum = 0

    for (let i = 2; i <= number; i++){
      sum = n1 + n2
      n1 = n2
      n2 = sum
    }

    return number ? n2 : n1
  }