Programming

It’s been quite a while since I’ve posted a programming challenge, that’s mainly because I haven’t heard a good one in a long time. I need my friends to do more interviews! Also, I’ve received emails in the past along the lines of “I really like the puzzles, and learn a lot from them, but can you post one a first year could solve”. That’s understandable, most of the puzzles I’ve posted previously might be tricky with only a few months of programming experience. So this programming puzzle is my attempt at monolithic di-ornithicide (aka killing two birds with one stone)

The longest repeated word

Write a method that takes a simple string as input, and outputs its longest repeated substring. When there are two of equal length, output whichever is first lexicographically.

Examples

• abba should return ’a’
• abracadabra should return ’abra’
• Mississippi should return ’iss’

You can get your solution to me any of the following ways, email, blogpost, trackback, IM, phonecall, even twitter it if your solution is <180 characters

Pretty please, I implore you, don’t post it as a comment You'll end up wondering why my blog ate all the rogue characters(< > ; etc). I can’t be bothered digging through 5K lines of someone elses PHP to try and stop it.

Some interesting solutions to a very straight forward programming question. The more interesting discussion arose in the comments. Are these questions any use? Is it fair to ask someone to write code during an interview? Should pseudo code answers be accepted to programming questions? For the record, my opinions are Yes, Yes and No, but thats for a different day.

This is a pretty simple one that Google apparently ask during their initial telephone interviews. None the less, trying to code with a phone at your ear and your potential boss at the other end of the line can prove difficult, especially when it's a little teaser like this …

Once again thanks a million to everyone with the solutions, good and bad, fast and slow, exponential and polynomial. I think seeing so many different solutions to a problem in vastly different languages is quite educational for me at least. I have 7 solutions to the puzzle this time. There were more submitted that were either duplicates (as in same method same language), or incorrect (as in worked for this data set only).

Time for another programming puzzle, this was given to a friend in an interview for a mobile phone operator. Apparently it maps neatly on to some problem that must regularly be solved in mobile phone networks, but seeing as said friend didn't get the job, I have no more information. Read on, just in case you end up in such an interview