When you are in an interview trying to solve problems, it is you general problem solving skills that will come to your aid. It is fruitless to try to memorize answers to specific questions. The problems presented are selected to prevent any such rote memorization.
One trick is for you to work through a specific example with the the problem. That may give crucial insight to the general solution. You should focus on the algorithm you use for the specific example.
Don't be afraid to talk through your thought process. This is actually encouraged. The interviewer likes to hear this. Remember to check for special cases once you think you have arrived at the general solution to the problem.
Know this. The correct solution to a given interview problem is usually very short. Around 10 to 15 lines of code should be sufficient. Therefore if you run out of room on the whiteboard, you are probably headed in the wrong direction. Next time I will cover the basics of Big-O notation.
A Little Bit of Crypto - I have been trying to figure out to "collision resistant" some of these standard hash functions are. It is a tough concept to get my head around. I figure...