Interviewers: stop the puzzle games !

I was active in looking for a job in a software company in the past three months (although I also did some contract work), and I failed at a puzzle game test because « I was too slow to answer the questions ».

Here are a some of the questions I was asked to do:

You are given a string variable $str.
Write PHP code to print the given string with every third letter removed.
For example, if input string is « Apple iPhone », the output should be « ApleiPon ».


Array $a contains integer numbers. Write PHP code to print an index of an element that contains the maximum value among array values that are even numbers (can be divided evenly by 2).


The questions and quizzes I’m going to talk about are the ‘basic’ quizzes, where your task is very near to algorithmic: eg write a function that sorts an array,
write a function that finds an integer inside an array, etc


They are many reasons for which I think this kind of questions do not make sense to choose between candidates.

  1. Some people will cheat
  2. It doesn’t show how you organize your code
  3. It doesn’t show how you work with others

Some people will cheat

In the book « The honest truth about dishonesty » by Dan Ariely, he explains that the most effect of cheating doesn’t come from big cheaters but rather from many cheaters.
In other words, they are not a few people who are tempted to put lots of effort to cheat.
However, they are many people who would put some effort to increase their score artificialy.
For example that could be done by using one or many of the following tricks (ordered from the difficult to the easiest):

  • If the test doesn’t require you to login, you could do the test twice, the first time providing information false information. This way, you can prepare
    yourself to the questions that are asked and achieve a score that is higher than what you could do normally
  • If you have unlimited time for the test (eg have one week to complete it), than you could very easily ask the help of a friend or even ask you question on
    a forum to make you smarter.

It doesn’t show how you organize your code

One of the biggest problem with quiz like problems is that you don’t encounter them in real life. You already have functions that can sort arrays in most of the
languages, or you could easily find a library that takes care of this for you.

The real difficulty in a codebase is not how to sort an array, or if that is the case your programmers are probably not that good. The real difficulty in a
codebase is how to organize your code.

I would also like to talk about a very positive experience when looking for a job : it was the test of the Financial Times Lab. They ask you a set of questions
which are « Stackoverflows » style of question, eg they ask you what’s the difference between

function helloWorld() {


var helloWorld=function () {

and why they give different results.

It doesn’t show how you work with others

Working with others is a huge part of what a programmer does. To achieve a task, some work must be done. But what takes most effort is the communication between
members of the team. If the communication doesn’t work well, your project isn’t going to meet it’s deadline.

Work in progress

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