How to prepare for coding interview in one week

Key takeaways:

• Day 1—Plan your preparation: Research the interview format of your target company, identify and list key topicsFor example, arrays, linked lists, trees, graphs, sorting algorithms, recursion, and Big-O notation. to revise, and then, choose practice platforms like Educative, or LeetCode where you can practice what you learn or review.

• Day 2—Review core data structures: Revise implementations, characteristics, and complexities of arrays, linked lists, stacks, queues, hash tables, trees, graphs, tries, and heaps.

• Day 3—Focus on basic algorithms: Revise and understand all the important algorithms like sortingFor example, Merge Sort, Quick Sort, Bubble Sort, Heap Sort, and Selection Sort., searchingLinear Search, Binary Search, DFS, and BFS. and some common coding interview patternsFor example, Two Pointers and Sliding Window., and their time complexities.

• Day 4—Dive into recursion, backtracking, and dynamic programming: Review concepts like base case, recursive case, backtracking rules, overlapping subproblems, optimal substructure, memoization and tabulation.

• Day 5—Study trees and graphs: Review binary trees, binary search trees, and graph structures. Then, practice tree traversalsIn-order, Pre-order, Post-order, and Level-order. and graph algorithms.

• Day 6—Practice mock interviews: Conduct 2-3 mock interviews using platforms like Educative or Pramp to simulate real interview process. Review and identify areas for improvement.

• Day 7—Final review and rest: Skim through your notes for a quick refresher. Then, take rest and stay relaxed to perform your best during the actual interview.

Preparing for a coding interview in one week is intense, but with the right strategy, you can make the most of the time you have. In this Answer, we'll go over a plan to help you maximize your preparation, so let's begin!

Day 1: Understand the interview process and plan the preparation

• Research the interview format: Look for the types of questions commonly asked by the company you are interviewing with. Sometimes the company itself shares such information on their website or via HR's email.

• Identify key topics to prepare: Carefully think and list down all the topics that you need to revise to prepare for the coding interview in just 7 days. This is the best time to highlight the concepts that you need to focus more. Make sure to cover the following:

  • Arrays and strings manipulation

  • Linked lists, stacks, queues, trees, graphs, hash maps/tables

  • Sorting and searching algorithms

  • Recursion and dynamic programming

  • Bit manipulation

  • Big-O notation

• Find the platforms to practice problem-solving:

• Here, Donald Knuth, father of algorithm analysis, highlights the value of practice over theory. In a short time, actively solving problems is more effective than passively reading only. Therefore, find online platforms that help you practice as many coding problems as you need. Some of the best players include Educative, LeetCode, or HackerRank.

• Take notes while you prepare: Make summarized notes for the key topics you revise, and jot down all the important points about them, including their time and space complexities in Big O notation. These notes will help you get a quick refresher before you end your preparation.

Day 2: Review core data structures

• Revise all the core data structures: Start by revising the most commonly used data structures, including their implementations, specific characteristics, use cases, and time and space complexities. Some of the basic data structures include:

• Practice relevant coding problems: Solve problems related to each data structure to understand their trade-offs. It is important to know when to use each data structure based on performance characteristics.

Day 3: Focus on algorithms basics

In coding interviews, it's often the basic algorithms that make the difference between a good solution and a great one. Let's go over some of the most important algorithms every candidate should know for their coding interview.

1. Sorting algorithms:

2. Searching algorithms:

3. Graph algorithms: If time allows, you can revise a few graph algorithms as well. For example, Dijkstra’s algorithm, Bellman-Ford algorithm, and Topological sort.

4. Common interview patterns: Other than these common algorithms, it is preferred to revise and understand some common coding interview patterns like Two Pointers, Sliding Window, Fast and Slow Pointers, and Merge Intervals.

Day 4: Dive into recursion, backtracking, and dynamic programming

1. Recursion: For recursion, quickly revise and familiarize yourself with the concept of base caseThe condition that stops the recursion. and recursive caseThe part where the function calls itself with modified parameters.. Then, practice a few commonly asked recursion coding problems like Factorial calculation, Fibonacci Sequence, String Reversal, and Power Calculation (e.g., pow(x, n)). While practicing these problems, visualize how recursive calls are made, and understand the flow and depth of recursion.

2. Backtracking: For backtracking, revise and understand how is it different from recursion. Then, practice common problems like N-Queens, Sudoku Solver, and Permutations and Combinations.

3. Dynamic Programming (DP): For DP, understand its two fundamental concepts, overlapping subproblemsSubproblems recur multiple times. and optimal substructureOptimal solutions can be constructed from optimal solutions of subproblems., and two of its techniques memoization (top-down) and tabulation (bottom-up). Then practice common DP coding problems like Fibonacci Sequence (compare recursive vs. DP solutions), Knapsack Problem (both 0/1 Knapsack and Unbounded Knapsack), Longest Common Subsequence (LCS), Longest Increasing Subsequence (LIS), and Coin Change.

Day 5: Study trees and graphs

Review and understand the structure and implementation of binary trees, binary search trees (BST), and graphs. For trees, go over the basic tree traversals:

• In-order

• Pre-order

• Post-order

• Level-order

For graphs, by this time, you might have already reviewed common graph algorithms like Dijkstra’s algorithm, Bellman-Ford algorithm and graph traversals like DFS and BFS, so just practice some common trees and graphs coding problems.

Day 6: Practice mock interviews

We all know that:

Practice makes a man perfect.

So, practice, practice and practice. When you prepare on your own, there are chances that you might miss out on some very basic concepts or probably do a certain task in a wrong way. This is where taking someone's help will do the magic. While preparing for the coding interviews, attempting mock interviews help in a great way. They help you get good at time management, debugging, and coding fluency.

Take at least 2-3 mock interviews using platforms like Educative, or Pramp.

Day 7: Final preparation and rest

• Go over any problem areas you struggled with in the mock interviews.

• Skim through your notes.

• Rest and stay relaxed to clear your mind for the actual interview. This is very important!

General tips for interview preparation

• Understand, Don’t Memorize: Try to comprehend the underlying principles or patterns instead of rote memorization. Understand common problem-solving approaches (e.g., divide and conquer, sliding window).

• Use flashcards or notes: For quick reviews of key algorithms, data structures, and time complexities.

• Time Management: Allocate specific time slots for each session to ensure comprehensive coverage.

• Take Breaks: Incorporate short breaks between sessions to maintain focus and prevent burnout.

• Ask for Help: If you're stuck on a problem, seek explanations from study groups, mentors, or Educative.

• Mock interviews: Simulate real interview environments to build confidence.

• Stay Calm: Focus on explaining your thought process rather than rushing through code during interviews.

Focused preparation with Educative

If you are aiming to apply for positions at big tech companies like MAANG (FAANG) —Meta (Facebook), Apple, Amazon, Netflix, and Google, try learning with our Paths. Each path is a condensed set of coding interview questions that ensures the coverage of essential coding patterns to give you the confidence needed to ace your coding interviews. These Paths are available in 5 languages, and some of them include:

• Speedrun the Meta Coding Interview: Top Problems in Python

• Speedrun the Apple Coding Interview: Top Problems in JavaScript

• Speedrun the Netflix Coding Interview: Top Problems in C++

• Speedrun the Google Coding Interview: Top Problems in Java

• Speedrun the LinkedIn Coding Interview: Top Problems in Go

• Speedrun the Microsoft Coding Interview: Top Problems in Python

• Speedrun the LinkedIn Coding Interview: Top Problems in C++

All of these Paths are available in JavaScript, C++, Java, and Go. Happy learning!