The 4 Week Plan to Nailing Your Next Coding & Technical Interview
Be prepared for blood, sweat, and possible stress tears.
*Scroll down for the mega list of free resources for technical interview prep at the end! Good luck :)
UPDATE: Added a new version of the interview cheat-sheet that can be downloaded & printed, and added new resources for data structure review!
Technical interviews are tough. Especially when there are about a million different questions they can possibly pull on you — it can feel impossible to be well-prepared. This guide aims to help you plan your review before your next big interview!
While I am no expert on technical interviews, I’ve gone through this interview-prep process twice each school year and have successfully gotten internship offers after interviews from both small and large companies. These questions are a mix of actual interview questions I’ve seen and also what I personally think is important to review.
Weekly Plan
Type 1: Practicing Problems Everyday
One way to break up review so that it is manageable is to set a consistent goal for each day. A simple, yet effective, approach is to do 1 easy and 1 medium problem each day & also 1 hard problem per each week. By the end of the month you will have finished 60 problems!
Type 2: Cramming in on the weekend
If we’re being realistic, most people don’t have the discipline to sit down for 2 hours each day for 4 weeks to review algorithms. What usually happens (for me anyway) is that I maybe spend about an hour per week day on review, and then cram for 10–12 hours on the weekend.
In general, I interview prep for approx. 15 hours each week and I split up my questions such that 50% of them are ‘easy’, 40% of them are ‘medium’ and 10% of them are ‘hard’ questions for each topic. I find that if you are able to complete and understand >50 coding problems before your interview — you should be in good shape.
Just remember…
Do whatever works for you and your schedule — just make sure that you’re giving an honest effort. Set realistic goals for each week and keep track of your progress.
When starting off, do not worry about being fast with coming up with your algorithms — understanding always comes first; speed will come naturally later on.
Week 1 — Arrays and Strings
Arrays and Strings are like the bread and butter of coding problems. While they are basic structures, they can easily get complicated and test you on more complex concepts.
Goal for the week: get into the ‘algorithm’ mindset and feel comfortable with basic data structures. Refresh your memory on basic concepts like recursion/binary search and handling off-by-one errors.
It’s likely you haven’t touched on these kinds of problems for a while so this week will mostly be for you to ‘ease’ into the next few weeks of technical review.
5 highly suggested review questions (in order of difficulty)
Longest Substring Without Repeating Characters
Week 2 — Binary Trees and Linked Lists
Everyone in CS loves binary trees — I have no idea why. I also don’t know why the binary tree is also always upside down… but I guess that’s another discussion altogether.
Goal for the week: start becoming critical of runtime and efficiency in your solutions. Understand BFS, DFS, & pros and cons of different approaches.
Binary tree and linked list problems are not all that different from strings & arrays. Many of the concepts will overlap — the algorithms just change slightly since the behavior of these data structures have unique features.
5 highly suggested review questions (in order of difficulty)
Remove nth node from linked list
Week 3 — Dynamic Programming & Greedy Algorithms | Focusing on Optimizations*
This is where the fun stuff happens. These questions are usually thrown to test your critical thinking and understanding of time/space complexity.
Goal for the week: start proactively challenging your own solutions and think of possible optimizations for either time or space. Be able to implement your solution both top-down (recursion & memoization) and bottom up (iteratively).
Being a good engineer means being able to explain why one approach is better than another & also have the ability to implement it in clean code.
5 highly suggested review questions (in order of difficulty)
Best time to buy and sell stock
*There is a trend of companies now phasing out dynamic programming problems in their interviews as they can be seen as unfair if the interviewee doesn’t know the ‘trick’. In my opinion I believe that DP problems are still a great way to review and improve algorithmic thinking, so as long as you’re ‘focusing on optimizations’ this week you should be covered!
Week 4 — More Graphs & Final Review
At this point you’ve covered basically 90% of what they will likely ask you. It’s important for you to review hard questions you encountered & go back to redo any problem may have gotten stuck on.
Goal for the week: review, review, and review all the concepts! Start doing mock interviews, timing yourself, and practice talking out loud when doing the problems.
While graphs are sometimes asked during interviews, I believe you can get by with just knowing the basic graph search algorithms.
And here are some extra general questions for review
Data Structure Review Resources
Resources for mock interviews and questions
“One leetcode a day keeps unemployment away!”
*The following resources are not free for long term use, however I highly recommend them as they have helped me and my friends ace our interviews & secure job offers!
This Holy Grail book: https://www.amazon.com/Elements-Programming-Interviews-Python-Insiders/dp/1537713949
During the interview cheat-sheet (I keep this paper next to me during a phone call coding interview)
For a guide on how to work through problems during a live coding challenge in an interview, you can read more here: Breaking It Down: How to Approach Any Technical Interview Problem
I’ll be updating this guide if I encounter more resources or remember new topics. Feel free to share your own experience / advice as well! If you could take a second to send a clap or two if this guide helped you in any way — I would really appreciate it ❤
*Please remember that your mileage may vary and that there is no substitute for hard work & truly understanding the fundamental concepts. Good luck! :)
