Interview Cheatsheet
==

This is a straight-to-the-point distilled list of technical interview Do's and Don'ts. Some of these may apply to only phone screens on whiteboard interviews but most will apply to both. I revise this list before each of my interviews to remind myself of them and eventually internalized all of them to the point I do not have to rely on it anymore.

For a detailed walkthrough of interview preparation, refer to the ["Preparing for a Coding Interview"](./) section.

### 1. Before Interview

**Do's**

- Prepare pen, paper and earphones/headphones.
- Find a quiet environment with good Internet connection.
- Stay calm and composed.
- Familiarize yourself with the coding environment (CoderPad/CodePen). Set up the coding shortcuts, turn on autocompletion, tab spacing, etc.
- Dress comfortably. Usually you do not need to wear shirt and tie.

### 2. Introduction

**Do's**

- Introduce yourself in a few sentences under a minute or two.
- Mention interesting points that are relevant to the role you are applying for.
- Sound enthusiastic! Speak with a smile and you will naturally sound more engaging.

**Don'ts**

- Spend too long introducing yourself. The more time you spend talk the less time you have to code.

### 3. Upon Getting the Question

**Do's**

- Repeat the question back at the interviewer.
- Clarify input format and range.
- Work through a small example to ensure you understood the question.
- Explain a high level approach even if it is a brute force one.
- Improve upon the approach and optimize. Reduce duplicated work and cache repeated computations.
- Think carefully, then state and explain the time and space complexity of your approaches.
- If stuck, think about related problems you have seen before and how they were solved. Check out the [tips](../algorithms) in this section.

**Don'ts**

- Ignore information given to you. Every piece is important.
- Jump into coding straightaway.
- Start coding without interviewer's green light.
- Appear too unsure about your approach or analysis.

### 4. During Coding

**Do's**

- Practice good coding style. Clear variable names, consistent operator spacing, proper indentation, etc.
- Defensive coding. Check for nulls, empty collections, etc.
- Explain what you are coding/typing to the interviewer, what you are trying to achieve.
- Type/write at a reasonable speed.
- Write in a modular fashion. Extract out chunks of repeated code into functions.
- Use the hints given by the interviewer.
- Practice whiteboard space-management skills.
- Demonstrate mastery of your chosen programming language.

**Don'ts**

- Remain quiet the whole time.
- Spend too much time writing comments.
- Use extremely verbose variable names.
- Copy and paste code without checking.
- Interrupt your interviewer when they are talking. Usually if they speak, they are trying to give you hints or steer you in the right direction.
- Write too big (takes up too much space) or too small (illegible) if on a whiteboard.

### 5. After Coding

**Do's**

- Scan through your code for mistakes as if it was your first time seeing code written by someone else.
- Check for off-by-one errors.
- Come up with more test cases. Try extreme test cases.
- Step through your code with those test cases.
- Look out for places where you can refactor.
- Reiterate the time and space complexity of your code.
- Explain trade-offs and how the code/approach can be improved if given more time.

**Don'ts**

- Immediately announce that you are done coding.
- Argue with the interviewer.

### 6. Wrap Up

**Do's**

- Ask questions. More importantly, ask good and engaging questions that are tailored to the company! Pick some questions from [this list](../non-technical/questions-to-ask.md).
- Thank the interviewer.

**Don'ts**

- End the interview without asking any questions.
- Ask about your interview performance. It can get awkward.