:: Eric Shamblen’s Puzzle Blog ::

The concept of the technical puzzle interview is now coming to India.  Judging from one article in the Deccan Herald, their take on it may be slightly different from ours.

In the article, a CEO is explaining to a Guru how the process works. He gives an example problem:

“We have eight balls all of the same size. Seven of them weigh the same, and one of them weighs slightly more. How can we find the ball that is heavier by using a balance and only two weighings? Here is the answer. We put four balls on either of pan and we would know which pan is heavier. Now, we must take the four balls from heavier pan and split them in-group of two and place in each pan of balance to get the heavier group. And we can physically feel and can distinguish the heavier of the two balls.”

Of course, unfortunately for Indian engineers hoping to get a job with Microsoft, this is the wrong answer. Feeling and distinguishing the heavier of two balls is, by definition, a weighing, which would bring the total number of weighings to three.  I leave it to the reader to figure out the correct answer if you’re not already familiar with this classic puzzle.

American engineers might have difficulty themselves applying for a job in India if the interviewers pose puzzles like the Guru’s response:

“Have you heard of this one? There are two pretty birds, which are not only colleagues but also close friends and are sitting close to each other on a tree. They are practically intertwined. One of the birds is partaking of the delicious ripe fruits of the tree with great relish. The other bird is maintaining a detached outlook, exhibiting no interest in eating the delicious ripe fruit and is judiciously presiding over the activities around.”

The answer?

“‘Dvasuparna sayuja sakhaya…,’ a popular puzzle of our ancient scriptures. To be precise, it is in Rigveda. It underscores the basic concept of the Vedic Trinity, the ‘matter’ around us, the ‘individual’ and the ‘power’ that holds everything. The supreme power and the individual appear to have their separate existence as two birds, and the third one is the ‘matter’ that is a passive agent of the universe. The tree represents mundane world or the nature. The vibrant bird enjoying the fruit represents soul that partakes of the myriad products of world. It acts out of its own volition (yoga of action). Supreme power, the other bird presides over the entire creation, as a friend, philosopher and guide.”

Take that, Bill Gates!

Smartkit, the developers of the Brainfit cognitive development software, recently announced a new intriguing product: The Runes. 

The puzzle contains 27 full-color sheets and over 300 puzzles,  including Sudoku, word searches, mazes and logic puzzles.  The answers link together to form more puzzles, which link together to form… who knows what.  No instructions or answers are included. 

According to the press release, “THE RUNES puzzle was delivered to an English man, from an acquaintance of his grandfather, with no clues to its origin or purpose but simply a box with a puzzle that entices the mind with meticulous letters, symbols and drawings.”

As of this writing, The Runes does not seem to be available on Amazon, but is available through Smartkit’s website for $37 plus shipping.

I have not had the opportunity to try out this puzzle myself, but from pictures like the one above it looks both fascinating and challenging. If anyone out there has a personal experience with this puzzle, please post comments below!

It has now become traditional for job applicants for technical positions at various companies - most famously, Microsoft - to have to solve off-the-wall logic problems or lateral thinking puzzles. Whether or not such puzzles actually are useful in determining the qualifications of an applicant are debatable, and in fact there have been strong arguments that interviewers tend to rely upon them far too much, ignoring such factors as the ability to work on a team, the ability to do the actual job being filled, and a host of other considerations that would be standard for applicants in any other position. Others say that, as part of a balanced mix of questions, such puzzles can show how well applicants can think on their feet.

Regardless of your take on the issue, the fact remains that such questions are in widespread use. Here are some resources to help you prepare for that upcoming interview - or just challenge yourself for fun:

How Would You Move Mount Fuji? Written by William Poundstone, who also wrote the puzzle books Labyrinths of Reason and Prisoner’s Dillemma. Considered by some to be the bible of the Microsoft-style interview, this book looks at the changing history of corporate hiring practices, the justifications for asking applicants problems that require straightforward logic or creative analysis, and includes numerous example questions and potential answers.

TechInterview A website run by Fog Creek Software cofounder Michael H. Pryor, it contains dozens of technical interview questions. Some relate to programming, but most require only general analytical or mathematical thinking. Answers are not always supplied, but on-site discussion threads show how different people approach the problems, which can be just as useful.

Microsoft Interview Questions This site contains a collection of actual questions asked by interviewers on the Microsoft main campus, divided into four categories. Unfortunately, no answers or approaches are given.

Interview Questions and Answers Here is a collection of all sorts of technical interview questions. Check out the “Analytical” and “Microsoft/Google” sections in particular. Site visitors propose possible solutions and vote on the best ones.

The Interview Brainteaser and its Discontents Joe Mabel not only discusses the general problems with using puzzles in job interviews, but supplies three real-life examples of interview brainteasers that went horribly wrong!