Interviews :

The approach
There are a few golden rules which you should follow when you are faced with an algorithms question at interview:

Make sure you understand the question. There is nothing worse than spending 15 minutes working on a problem, to find that you've slightly misunderstood what was being asked of you. One great way to make sure that you have understood correctly is to restate the problem to the interviewer. So for example, if you were asked to find the third smallest value in a binary search tree, you could start by drawing out a tree and making sure that you are identifying the node which the interviewer expects.

Talk through what you are doing. Part of what an interviewer is looking for in your technical interview is your thought processes when you tackle a problem. So even if you don't get to the correct solution, you can demonstrate that you are able to work logically and methodically. But this is only possible if you let the interviewer know what you are doing. So rather than standing in front of a white board and scribbling in silence for five minutes, provide a running commentary on what you are doing and why.

Start with a naive solution. In most problems which you will be presented with there will be a fairly highly optimized solution possible. But don't let that distract you! Start out by trying to find the simplest, least clever solution to the problem possible. If you manage that then a) you'll be feeling pretty good about yourself for solving the problem, and b) it opens up a whole field of questions for the interviewer about ways in which you can iterate on and improve your solution.