Tech-Interview Riddles
An anonymous submitter writes "A computer engineering student at UC Berkeley has made a comprehensive archive of riddles from technical interviews. Very challenging and loads of fun. Also useful for interview preparation."
for more tech interview questions and answers try http://www.techinterview.org/
I did a lot of interviews at MS when I was there, and I quickly learned not to ask riddles. First off, it makes people who don't get them uncomfortable and angry. Second, it doesn't actually show that the person can write software.
I used a much simpler approach, so simple most people think its silly. But thats the point; nobody leaves the interview thinking they were tricked or duped. I always started with implementation of strcpy(). Half of the candidates failed right there! They took most of the hour to get it right (or not), but were able to see point-blank that they were not ready for the job.
Next, I would ask about crashing cases, and if they figured out overlapping memory locations, have them write a 'fixed' version. This weeded out another big chunk. After that, I went into some color counting algorithms.
I stayed well withing the field of what the candidate would expect, and did not try to trick him or make him nervous with off the wall riddles.
This approach worked great, and didn't leave anyone feeling robbed and abused. The ability to solve riddles *is* an indicator of how smart the person is, but it is *not* an indicator of how good a programmer they will be.