Saturday, November 19, 2011

Origins of code interviews questions

Have you ever wondered where are all those brain teasing ,programming interview questions coming from? You can find them gathered and published in at least a dozen of web sites and books. You read the book before the interview and try to memorize, ideally understand the answers. Then when the interview is over, you forget them.
I was curious where are any of those problems used in practice. I mean, there must be some application. For example, take the short formula (n&(n-1)) ==0, where do you ever need to determine if a number is a power of 2? Of course, since computers are using binary arithmetics, you would think this has many application. I tried googling and I could not find any. I found out about perfect numbers http://mathforum.org/dr.math/faq/faq.perfect.html that are computed based on but I don't think you need to verify if a number is a power of 2 there.
Finding a missing integer in an array of consecutive integers has a simple solution using bit manipulation. I was able to find one application thanks to this site: http://blogs.oracle.com/malkit/entry/finding_missing_value
and after reading it, I got the idea of another application: to find a missing packet in a sequence of received packets, where each one has a sequence number (like in TCP protocol).

No comments:

Post a Comment