Clarifying QuestionsAsk clarifying questions to make sure you understand the scope of the problem so that you'll be solving the right problem. The interviewer may be testing you to see if you know how to gather requirements and communicate.
Don't rush into coding and risk solving the wrong problem or missing the interviewer's point. This is your chance to shine, to show the interviewer that you can communicate well and get to the heart of problems.
Identify PatternIdentify patterns: does this problem look like a search, dynamic programming, graph, or sorting problem? Don't have to tell your interviewer. This step is for yourself.
Examples and Test CasesCome up with examples and test cases. This will make the problem concrete and provide test cases with which you will test your solution later on.
Brainstorm ApproachesCome up with 2-3 approaches and briefly run them by the interviewer but don't write up any code yet. If you need some time to come up with the optimal solution, you can start by outlining what a brute force solution would look like.
CodeCode quickly, systematically, and cleanly.
TestTest & debug
Don't forget to double check your work and walk through the solution using one of the test cases you came up with.
Shrunk and White of Programming When you put down that you know a certain programming language or languages on your resume, you are setting certain expectations for the interviewer. I would strongly caution against putting down "expert" in a language unless you invented or are one of the language's maintainers. You are giving your interviewer the license to quiz you on programming language lore. There are a handful of concepts that are considered "standard" knowledge for each language which go broadly beyond syntax and general semantics. These concepts commonly involve major pitfalls in a given language and the idiomatic technique for negotiating these pitfalls and writing efficient and maintainable code. Note, although the concepts are considered idiomatic, you can seldom infer them from knowledge of syntax and semantics alone. The tricky part here is that most courses that teach a particular programming language do not cover these idiomatic techniques and eve…