Top Data Structures And Algorithms Every Developer Must Know
Many shudder at the thought of a coding interview. It can be stressful, grueling, and challenging. Oftentimes, it can be a struggle simply to know what topics to prepare.
today, you will be introduced to the primary data structures and algorithms that are tested in a coding interview. After reading this article, you should have a good idea of what you need to prepare for to land your dream job.
We will cover the following:
Master data structures and algorithms for coding interviews
Prepare for your coding interview with hands-on practice for all common interview questions.
Preparing For The Unexpected What Might Surprise You About The Google Engineering Interview Process
Despite all the industry hype about how only the best of the best will ever grace the Google hallways, Phil says that the biggest surprise probably is that you dont need to be perfect.
Youll be presented with very challenging problems to solve, and its often ok if you arent able to come up with a complete working solution .
A big part of what youre being evaluated on is your analytical ability. Essentially your approach to understanding and solving complex problems. Of course, its best if you can completely solve the problem given to you, but its not an automatic failure if you cant do that.
In keeping with the topic of flawlessness: Phil says that its also possible to be hired even if you didnt do well in one of the interviews.
Google uses a hiring committee of experienced engineers and managers who review all the information available about a candidate . The hiring committee can decide to move forward with a candidate, even if one of the interviewers didnt feel the candidate should be hired. Sometimes theyll also request that a candidate repeat a portion of the interview to assess if the one bad interview was just an off day.
Common Functional Testing Process
Most fundamental testing moves through the same 4 steps, widening in test scope at each step. The process starts with unit testing to evaluate individual components and ends with acceptance testing to evaluate how the product relates to the original plan.
Lets take a deeper look at each step!
Unit testing is used to test individual components of a program separate from the other components. For example, in object-oriented programs, you would unit test an individual class before trying to connect it to other classes.
This type of testing is often completed by the developer to catch defects without needing to wait for a full test cycle. Unit testing is most often automated to get quick results but can be done manually.
Integration testing is used to test how multiple connected program components work together. This type of testing is often done after unit testing first, validate each component individually, then how the components work together.
For example, you could integration test a parent class and two related child classes to ensure that test case inputs are assigned to the expected class with all expected attributes.
Integration testing is completed by the developer to verify that connected components join together seamlessly, usually through automated tests.
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Understanding Big O Notation
Big O notation is an asymptotic analysis that describes how long an algorithm takes to perform. In other words, its used to talk about how efficient or complex an algorithm is.
Big O describes the execution time, or run time, of an algorithm relative to its input N N N as the input increases. Though we can analyze an algorithms efficiency using average-case and best-case, we typically use worst-case with Big O notation.
Today, you will learn about time complexity, but take note that space complexity is also an important concept to understand. Runtime complexity can be a difficult concept to grasp at first, so lets look at some examples.
Learn About Microsoft’s Culture
Most candidates fail to do this. But before investing tens of hours preparing for an interview at Microsoft, you should take some time to make sure it’s actually the right company for you.
Microsoft is prestigious and it’s therefore tempting to ignore this step completely, but the prestige of the company, in itself, won’t make you happy day-to-day. It’s the type of work and the people you work with that will.
If you know engineers who work at Microsoft , talk to them to understand what the culture is like. In addition, we would also recommend reading the following resources:
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My Guide To Preparing For The Google Technical Interview
With over ten years of programming experience and a CS degree, it took me about a month and a half of daily practice to get ready for the interview. Ready, for me, is ambitiously defined as the ability to tackle almost any technical interview question in 30 minutes or less and reach an optimal solution. The following is based upon what I did to prepareyour mileage may vary.
- About two years of solid coding experience
- Pencil and paper
- Your favorite algorithms bookIntroduction to Algorithms, The Algorithm Design Manual, and Programming Pearls are a few good choices. Might I suggest you go low tech and buy physical copies?
- Two or three hours a day
- Highly recommended: Whiteboard
- Optional: MIT OpenCourseware or another learning site
1) Learn as much as you can about the Google interview process
Just like an incomplete understanding of a technical question will ruin you in the actual interview, misinformation will derail your preparation leading up to it. I learned this the hard way when I failed at my first attempt after emphasizing brain teasers over studying algorithms and data structures.
Once you have a solid foundation, Id recommend following up by reading CTCI. Particularly focus on chapters 5 and 6 entitled Behavioral Questions and Technical Questions.
Test Case Closure And Analysis
This step is about recovering solid, reportable takeaways from the tests. Most companies will have you write either a daily or weekly report that summarizes how each test went and what changes will be made as a result of the test.
From here you can either:
- Tweek the test and repeat for more information .
- Return to develop solutions for the product using the test results
Using agile testing practices, youll complete this test cycle before you create the product code as well as after. This allows you to speed up development as you keep the test specifications in mind during product development.
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What Exactly Is Microsoft Looking For
At the end of each interview your interviewer will grade your performance using a standardized feedback form. Here is some of the information that’s contained in the form.
A) Interview notes
Interviewers will file the notes they took during the interview. This usually includes: the questions they asked, a summary of your answers and any additional impressions they had .
B) Competencies assessment
Your interviewer will then grade you on different competencies. They will be trying to determine if you meet the bar or not for each competency they are interested in. In other words, you’ll need to convince them that you are at least as good as, or better than, the average current Microsoft SDE at the level you’re applying for .
The exact list of competencies Microsoft looks for varies depending on groups, roles, and levels. But here are some of the main ones that are usually discussed by Microsoft recruiters:
- Passion for technology
C) Hiring recommendation
Each interviewer will give a hiring recommendation at the end of the interview. The different options are along the lines of: “Strong hire”, “Hire”, “No hire”, “Strong no hire”.
D) Suggested follow-ups
Land Your Dream Job As A Software Engineer At Google
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How Does It Work
There are many ways to test software. In general, developers first decide a behavior or feature that needs validation, create a test that confirms the feature, then either correct the feature or move on if it passes.
In early software design philosophy, testing was undervalued and often completely ignored. Now, programs have become more complex, are implemented at a greater scale, and to a more diverse array of devices and operating systems.
Software testing has become an essential part of the modern development cycle. It acts as an ongoing form of quality assurance and verifies that the software can respond to all possible use cases or environments.
Here are some of the benefits of software testing:
- Ensures full functionality: Ensure all targeted features are included in the final product.
- Early warning: Warns of program defects during development, before they negatively affect user experience.
- Verified Device Support: Test software functionality on all targeted devices to ensure consistent user experience.
- Incremental development: Testing frameworks allow you to track measurable progress toward fulfilling all program requirements.
What To Learn Next
Congratulations on finishing your first look into the world of software testing! If youre interested in continuing your testing career, the next step is to learn an automation framework. Selenium is one of the most used testing frameworks in the world and can be learned fast!
To help you pick up Selenium quickly, Educative has created the course Design a Test Automation Framework with Selenium and Java. This concise course teaches you the basics of Selenium and provides dozens of interactive examples. By the end, youll be a master of building the types of complex automated tests interviewers are looking for.
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Why Should You Learn Data Structures And Algorithms
The coding interview tests for your problem-solving abilities and understanding of computer science concepts. Usually, you are given about 30 – 45 minutes to solve one complex problem.
This is where data structures and algorithms come in. These interviews will test you on topics such as linked lists, queues, sorting, searching, and much more, so its crucial to prepare.
Not only do companies want to test your technical knowledge, but they also want to evaluate your problem-solving skills.
If you get the job, you will often face bugs that you need to fix, and companies want to make sure that you can overcome these obstacles.
Furthermore, you will often use specific data structures and algorithms to optimize your code so that it runs as efficiently as possible.
Fundamentals Of An Em Interview
Engineering Managers in most tech companies are expected to play this intersectional role between People, Tech, and Product/Business. They are entrepreneurs for their own little startups and are held accountable for its success. The real question every company wants to answer is Can this person drive sustainable, long-term success for this area of the business? So they model the interview process to capture signals that can give them reasonable confidence about the candidates ability to drive that sustainable, long-term success. Obviously, it is impossible to categorically determine that, so companies resort to reasonable proxies. The proxies that Ive seen end up falling into these categories:
- Technical Domain Experience
Lets look at each of these in detail and see how they manifest in various interview formats across different companies:
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Tips For Practicing Coding Challenges
There is no shortcut or magic wand for practicing coding challenges. Here are some basic tips to guide you through the preparation stage.
Keep time in mind. The coding interview will be timed, so its important to prepare with that in mind. If you are used to preparing under a time constraint, it will be far less stressful during the actual interview.
Know your weak spots. As you prepare, take note of your weak spots. Everyone has them. Google has stated that they care about your thought process, so if you come up against a weak spot, talk through it. This will demonstrate your eagerness to improve.
Know the common pitfalls. There are three big pitfalls when it comes to a Google interview: not knowing the Big-O complexity of an algorithm, having no knowledge of Googles expectations, and not articulating your problem-solving process. Keep these pitfalls in mind as you work.
Articulate your process. Google wants to hear about your thought process. As you practice, get used to explaining why and what you are doing. Those with a clear sense of how they work stand out.
Behavioral interviews are often overlooked by software development candidates. In reality, this is the interview that sometimes will make or break you as a candidate. Google cares deeply about their values, so if you come unprepared for these questions, theyll notice it.
Experience And Skill Levels
Hiring managers evaluate how relevant your skills and work experience are to the role youâre interviewing for.
Key areas of evaluation are:
- Your problem-solving abilities
- Your ability to apply programming concepts to different problems
- Your ability to find multiple solutions to a problem and identify the most optimal one
The Google Phone Interview
For the phone screen, you are interviewed by at least one Google employee who provides you with a coding question. You share a Google document with the interviewer and use it to write code for the question asked by the interviewer.
Protip: Coding in Google Docs sucks, but if you update your preferences it can make your life 1000x better. Learn how to do that here.
This interview will focus on your ability to produce code without an IDE . Typically, the question asked will be one that can be solved by a brute-force solution, and then progressively improved upon.
The phone interview is about 30-45 minutes. Assuming you did well, the Google recruiter will reach back out to you to give you the next steps if they decide to move along with you.
Dont be disappointed if they ask to do a second phone interview. Thats totally normal if they dont feel like they were able to adequately assess you the first time and doesn’t have any bearing on your later interviews.
Google Software Engineer Interview Faqs
Q.How long are Google Software Engineer interviews?
A. The duration of each interview round can be 30-45 minutes long, depending on the round. From application to offer, the overall duration of the hiring process can range from a few weeks to a few months, depending on the seniority of the role.
Q. Will the candidate be asked only coding questions in all the interviews?
A. No. Candidates will be asked questions on various domains like – technical, system design, and behavioral to test whether the candidate is a good fit in the Google workspace.
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Top 15 Google Coding Interview Questions
Find the kth largest element in a number stream
Problem Statement: Design a class to efficiently find the Kth largest element in a stream of numbers. The class should have the following two things:
The constructor of the class should accept an integer array containing initial numbers from the stream and an integer K.
The class should expose a function add which will store the given number and return the Kth largest number.
Find k closest numbers
Problem Statement: Given a sorted number array and two integers K and X, find K closest numbers to X in the array. Return the numbers in the sorted order. X is not necessarily present in the array.
Delete node with given key
Problem statement: You are given the head of a linked list and a key. You have to delete the node that contains this given key.
Copy linked list with arbitrary pointer
Problem statement: You are given a linked list where the node has two pointers. The first is the regular next pointer. The second pointer is called arbitrary_pointer and it can point to any node in the linked list.
Your job is to write code to make a deep copy of the given linked list. Here, deep copy means that any operations on the original list should not affect the copied list.
Mirror binary trees
Problem statement: Given the root node of a binary tree, swap the left and right children for each node.
Find all paths for a sum
Longest substring with no more than k distinct characters
Equal subset sum partition
Getting Noticed By Google
Google receives more than two million resumes but hires only around 4000 employees every year so its not easy to get noticed by recruiters for interview calls. Take the referrals through some connections working in these companies or you can take the help of LinkedIn and online coding platforms to increase your chances for interview calls. Below are some points that will help you in getting the call for interviews
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