A practical, fun approach to computer science fundamentals, as seen through the lens of common programming interview questions. This is the Python version of our book.
Wanted to work at an exciting futuristic company? Struggled with an interview problem thatcould have been solved in 15 minutes? Wished you could study real-world computing problems? Updated to reflect changing techniques and trends, this new fourth edition provides insider guidance on the unique interview process that today's programmers face.
Online coding contests are being used to screen candidate pools of thousands, take-home projects have become commonplace, and employers are even evaluating a candidate's public code repositories at GitHub—and with competition becoming increasingly fierce, programmers need to shape themselves into the ideal candidate well in advance of the interview.
This edition combines a thoroughly revised basis in classic questions involving fundamental data structures and algorithms with problems and step-by-step procedures for new topics including probability, data science, statistics, and machine learning which will help you fully prepare for whatever comes your way. Programming Interviews Exposed teaches you the interview skills you need to stand out as the best applicant to help you get the job you want.
Elements of Programming Interviews EPI aims to help engineers interviewing for software development positions. The primary focus of EPI is data structures, algorithms, system design, and problem solving. The material is largely presented through questions. This is a larger-format version of Elements of Programming Interviews in Java. Specifically, the font size is larger, and the page size is 7"x10" the regular format uses 6"x9".
The content is identical. This is the Java version of our book. Get ready for interview success Programming jobs are on the rise, and the field is predicted to keep growing, fast. Landing one of these lucrative and rewarding jobs requires more than just being a good programmer. Programming Interviews For Dummies explains the skills and knowledge you need to ace the programming interview.
Interviews for software development jobs and other programming positions are unique. This book demystifies both sides of the process, offering tips and techniques to help candidates and interviewers alike.
Prepare for the most common interview questions Understand what employers are looking for Develop the skills to impress non-technical interviewers Learn how to assess candidates for programming roles Prove that you or your new hires can be productive from day one Programming Interviews For Dummies gives readers a clear view of both sides of the process, so prospective coders and interviewers alike will learn to ace the interview. Elements of programming guide What is Computer Programming and How to Become a Computer Programmer PC writing computer programs is the cycle that experts use to compose code that trains how a PC, application or programming program performs.
Some short summary of the topics in discussion would b Yes, this book is full of interview questions. Some short summary of the topics in discussion would be much more useful for the readers.
Also, the solutions are often too succinct. Of, there are also errors and ambiguity in some of the questions. May 17, Sourabh Daptardar rated it it was amazing. Elements of Programming Interviews is the best collection of algorithmic puzzles and exercises that I have seen.
Whether you are preparing for programming interviews or simply want to hone your algorithmic skills, this book is for you. With concise explanations, asymptotic analysis and optimised code, this book offers a great reference to the self learners.
In a course for design and analysis of algorithms, the book can also complement the standard textbooks like CLRS, Dasgupta-Papdimitrou-Vazir Elements of Programming Interviews is the best collection of algorithmic puzzles and exercises that I have seen.
In a course for design and analysis of algorithms, the book can also complement the standard textbooks like CLRS, Dasgupta-Papdimitrou-Vazirani, Kleinberg-Tardos as assignment problems, as standard textbooks stop at pseudocode level, but knowing the nuances of implementations helps in practice.
This book is most effective for self improvement of algorithmic thinking -- if you code the solutions yourself and compare with the analysis and solutions offered.
Overall, a great book to have! Jul 14, Quang Huynh rated it it was amazing. I am not a fan of textbook style representation. Thick textbooks require skimming skill which I personally find painful when reading technical materials - I either skip some important details, or stay on some trivial matter too long.
EPI keeps it lean and clean, the book is by no mean for beginners but if you need a comprehensive yet succinct book to revise and enhance your Algorithm knowledge, this is what to get. Everything is to the point and sometimes too briefly explained that it takes a whi I am not a fan of textbook style representation.
Everything is to the point and sometimes too briefly explained that it takes a while to figure out, but that's a very enjoying process on its own.
This is the best interview preparation book I've known, it simply out-performs the more popular Gayle's. Many problems are pretty practical. If you do have a few months to spare, grab this, your time won't be wasted.
Apr 14, Heriberto Avendano is currently reading it. Grind never ends. Best SWE interview book. Oct 07, Vishwanath Gulabal rated it it was amazing. Must read for interview preparation. This book is way better than CTCI.
Instead of just teaching you programming interview tricks, it actually dives deep into various algorithmic topics. Dec 16, Sefa rated it it was amazing Shelves: computer-science , programming.
As good as "Cracking the coding interview", if not better. Twice as many problems and solutions than CCI. However, unlike CCI, it doesn't have enough review before each topic. You need to check out another source there are plenty for that.
I would love to see a similar book for Python. Dec 20, Piyush Maheshwari rated it it was amazing. Like its earlier editions, this guide covers what software companies and IT departments want their programmers to know and includes plenty of helpful hints to boost your confidence.
Looks at current job search and hiring processes, such as Java Programming Interviews Exposed. If you are a skilled Java programmer but are concerned about the Java coding interview process, this real-world guide can help you land your next positionJava is a popular and powerful language that is a virtual requirement for businesses making use of IT in their daily operations. For Java programmers, this reality offers job security and a wealth of employment opportunities.
But that perfect Java coding job won't be available if you can't ace the interview. If you are a Java programmer concerned about interviewing, Java Programming Interviews Exposed is a great resource to prepare for your next opportunity.
Some solutions use relatively advanced machin- ElementsOfProgrammingInterviews. You will encounter such problems in an interview only if you have a graduate degree or claim specialized knowledge. Most solutions include code snippets. Programs concerned with concurrency are in Java. Source code, which includes randomized and directed test cases, can be found at the book website. System design problems are conceptual and not meant to be coded; a few algorithm design problems are also in this spirit.
At the end of many solutions we outline problems that are related to the original question. A variant is a problem whose formulation or solution is similar to the solved problem. Approximately a fifth of the questions in EPI have a white ninja or black ninja designation. White ninja problems are more challenging, and are meant for applicants from whom the bar is higher, e. Questions without a ninja label should be solvable within an hour-long interview and, in some cases, take substantially less time.
Often, your interviewer will give you a brief suggestion on how to proceed with a problem if you get stuck. We provide hints in this style on Page Level and prerequisites We expect readers to be familiar with data structures and algorithms taught at the undergraduate level. The chapters on concurrency and system design require knowledge of locks, distributed systems, operating systems OS , and insight into commonly used applications.
Some of the material in the later chapters, specifi- cally dynamic programming, graphs, and greedy algorithms, is more advanced and geared towards candidates with graduate degrees or specialized knowledge. The review at the start of each chapter is not meant to be comprehensive and if you are not familiar with the material, you should first study it in an algorithms textbook. There are dozens of such texts and our preference is to master one or two good books rather than superficially sample many.
Algorithms by Dasgupta, et al. Since our focus is on problems that can be solved in an interview, we do not include many elegant algorithm design problems. Similarly, we do not have any straightforward review problems; you may want to brush up on these using text- books.
You can get a better sense of the problems not included in this document by visiting the EPI website. For example, the patterns chapter in this document does not refer to problems that illustrate the pattern being discussed. Similarly, we do not include the study guide from EPI, which specifies the problems to focus on based on the amount of time you have to prepare. This document is automatically built from the source code for EPI.
There may be abrupt changes in topic and peculiarities with respect to spacing because of the build process. Reader engagement Many of the best ideas in EPI came from readers like you. The study guide, ninja notation, and hints, are a few examples of many improvements that were brought about by our readers. The companion website, ElementsOfProgrammingInterviews. It also has links blog postings, code, and bug reports. Please fill out the EPI registration form, bit.
You can always communicate with us directly—our contact information is on the website. Ford The most important part of interview preparation is knowing the material and prac- ticing problem solving. However, the nontechnical aspects of interviewing are also very important, and often overlooked.
These aspects of interviewing are summarized in Table 1. Identify companies that you are interested in, and, ideally, find people you know at these companies. Perform an initial phone screening, which often consists of a question-answer session over the phone or video chat with an engineer. You may be asked to submit code via a shared document or an online coding site such as ideone.
Go for an on-site interview—this consists of a series of one-on-one interviews with engineers and managers, and a conversation with your Human Resources HR contact. Receive offers—these are usually a starting point for negotiations.
Note that there may be variations—e. The screening may involve a homework assignment to be done before or after the conversation. The on-site interview may be conducted over a video chat session. Most on-sites are half a day, but others may last the entire day. For anything involving interaction over a network, be absolutely sure to work out logistics a quiet place to talk with a landline rather than a mobile, familiarity with the coding website and chat software, etc.
Getting Ready Table 1. The experience will help you feel more comfortable with interviewing and you may discover you really like a company that you did not know much about. I would like to apply these abilities at XYZ. The most important points—the ones that differentiate you from everyone else—should come first.
Maintaining a logical flow, though desirable, is secondary compared to this principle. As a consequence, you should not list your programming languages, course- work, etc. You should list significant class projects this also helps with keywords for HR.
Use few fonts. Include contact information, a LinkedIn profile, and, ideally, a URL to a per- sonal homepage with examples of your work. Include design documents as well as a link to your version control repository. If you can work at the company without requiring any special processing e.
It is better to get something written up quickly, and then refine it based on feedback. Over two pages is probably not a good idea. Getting Ready Mock interviews Mock interviews are a great way of preparing for an interview.
Get a friend to ask you questions from EPI or any other source and solve them on a whiteboard, with pen and paper, or on a shared document.
Have your friend take notes and give you feedback, both positive and negative. Make a video recording of the interview. You will cringe as you watch it, but it is better to learn of your mannerisms beforehand. Ask your friend to give hints when you get stuck. In addition to sharpening your problem solving and presentation skills, the experience will help reduce anxiety at the actual interview setting. If you cannot find a friend, you can still go through the same process, recording yourself.
This is followed by five to fifteen minutes of questioning on basic programming concepts. The core of the interview is one or two detailed design questions where the candidate is expected to present a detailed solution on a whiteboard, paper, or integrated development environments IDEs. Depending on the interviewer and the question, the solution may be required to include syntactically correct code and tests.
Approaching the problem No matter how clever and well prepared you are, the solution to an interview problem may not occur to you immediately. Here are some things to keep in mind when this happens. Clarify the question: This may seem obvious but it is amazing how many inter- views go badly because the candidate spends most of his time trying to solve the wrong problem. If a question seems exceptionally hard, you may have misunder- stood it. A good way of clarifying the question is to state a concrete instance of the problem.
Feel free to ask the interviewer what time and space complexity he would like in your solution. If you are told to implement an O n algorithm or use O 1 space, it can simplify your life considerably. It is possible that he will refuse to specify these, or be vague about complexity requirements, but there is no harm in asking.
Work on concrete examples: Consider Problem 5. This problem may seem difficult at first. However, if you start working out which doors are going to be open up to the fifth door, you will see that only Door 1 and Door 4 are open.
This may suggest to you that the door is open only if its index is a perfect square. Once you have this epiphany, the proof of its correctness is straightforward. Keep in mind this approach will not work for all problems you encounter.
Strategies For A Great Interview Spell out the brute-force solution: Problems that are put to you in an interview tend to have an obvious brute-force solution that has a high time complexity com- pared to more sophisticated solutions. For example, instead of trying to work out a DP solution for a problem e. Advantages to this approach include: 1. Be warned that this strategy can sometimes be detrimental if it takes a long time to describe the brute-force approach.
Think out loud: One of the worst things you can do in an interview is to freeze up when solving the problem. It is always a good idea to think out loud. On the one hand, this increases your chances of finding the right solution because it forces you to put your thoughts in a coherent manner. On the other hand, this helps the interviewer guide your thought process in the right direction. Even if you are not able to reach the solution, the interviewer will form some impression of your intellectual ability.
Apply patterns: Patterns—general reusable solutions to commonly occurring problems—can be a good way to approach a baffling problem. Examples include finding a good data structure, seeing if your problem is a good fit for a general al- gorithmic technique, e. Patterns are described in much more detail in Chapter 4. Presenting the solution Once you have an algorithm, it is important to present it in a clear manner.
However, it is far more important that you use the language you are most comfortable with. Here are some things to keep in mind when presenting a solution. Libraries: Master the libraries, especially the data structures. Do not waste time and lose credibility trying to remember how to pass an explicit comparator to a BST constructor. Remember that a hash function should use exactly those fields which are used in the equality check.
A comparison function should be transitive. Hash, equals, and compare functions are good candidates for deferred implementation. Specify that you will handle main algorithm first, then corner cases. Add TODO comments for portions that you want to come back to. Manage the whiteboard: You will likely use more of the board than you expect, so start at the top-left corner. Have a system for abbreviating variables, e. Make use of functions—skip implementing ElementsOfProgrammingInterviews.
Test for corner cases: For many problems, your general idea may work for most inputs but there may be pathological instances where your algorithm or your implementation of it fails. For example, your binary search code may crash if the input is an empty array; or you may do arithmetic without considering the possibility of overflow.
It is important to systematically consider these possibilities. If there is time, write unit tests. Small, extreme, or random inputs make for good stimuli. Often the code to handle obscure corner cases may be too complicated to implement in an interview setting. If so, you should mention to the interviewer that you are aware of these problems, and could address them if required.
Syntax: Interviewers rarely penalize you for small syntax errors since modern IDE excel at handling these details. However, lots of bad syntax may result in the impression that you have limited coding experience.
Once you are done writing your program, make a pass through it to fix any obvious syntax errors before claiming you are done. We use the Google coding style standards in this book, and advise you to become proficient with them. They are available at code. Candidates often tend to get function signatures wrong and it reflects poorly on them.
For example, it would be an error to write a function in C that returns an array but not its size. Use const as appropriate. Memory management: Generally speaking, it is best to avoid memory manage- ment operations altogether. The run time environment will automatically deallocate the object a scoped pointer points to when it goes out of scope. If you explicitly allocate memory, ensure that in every execution path, this memory is de-allocated. See if you can reuse space.
For example, some linked list problems can be solved with O 1 additional space by reusing existing nodes. You should use search and social networks to learn more about the people interviewing you. Letting your interviewers know that you have researched them helps break the ice and forms the impression that you are enthusiastic and will go the extra mile.
For fresh graduates, it is also important to think from the perspective of the interviewers as described in Chapter 3. Once you ace your interviews and have an offer, you have an important decision to make—is this the organization where you want to work? Interviews are a great time to collect this information. Interviews usually end with the interviewers letting the candidates ask questions. You should make the best use of this time by getting ElementsOfProgrammingInterviews.
Strategies For A Great Interview the information you would need and communicating to the interviewer that you are genuinely interested in the job. Based on your interaction with the interviewers, you may get a good idea of their intellect, passion, and fairness. This extends to the team and company. In addition to knowing your interviewers, you should know about the company vision, history, organization, products, and technology.
You should be ready to talk about what specifically appeals to you, and to ask intelligent questions about the company and the job. Prepare a list of questions in advance; it gets you helpful information as well as shows your knowledge and enthusiasm for the organization. You may also want to think of some concrete ideas around things you could do for the company; be careful not to come across as a pushy know-it-all. All companies want bright and motivated engineers.
However, companies differ greatly in their culture and organization. Here is a brief classification. Startup, e. Such companies do not have time to train new hires, and tend to hire candidates who are very fast learners or are already familiar with their technology stack, e.
Mature consumer-facing company, e. Such companies have a deeper technology stack, much of which is developed in-house. They have the resources and the time to train a new hire.
Enterprise-oriented company, e. Government contractor, e. The tool chain and development practices at such companies tend to be very mature. General conversation Often interviewers will ask you questions about your past projects, such as a senior design project or an internship. The point of this conversation is to answer the following questions: Can the candidate clearly communicate a complex idea?
This is one of the most important skills for working in an engineering team. If you have a grand idea to redesign a big system, can you communicate it to your colleagues and bring them on board? It is crucial to practice how you will present your best work. Being precise, clear, and having concrete examples can go a long way here.
Candidates communicating in a language that is not their first language, should take extra care to speak slowly and make more use of the whiteboard to augment their words. We always want our colleagues to be excited, energetic, and inspiring to work with.
Hence, when you are asked to describe a project from the past, it is best to pick something that you are passionate about rather than a project that was complex but did not interest you. Is there a potential interest match with some project? The interviewer may gauge areas of strengths for a potential project match. If you know the requirements of the job, you may want to steer the conversation in that direction. Other advice Be honest: Nobody wants a colleague who falsely claims to have tested code or done a code review.
Dishonesty in an interview is a fast pass to an early exit. Similarly, if you have seen a problem before, you should say so. Be sure that it really is the same problem, and bear in mind you should describe a correct solution quickly if you claim to have solved it before. Interviewers have been known to collude to ask the same question of a candidate to see if he tells the second interviewer about the first instance.
An interviewer may feign ignorance on a topic he knows in depth to see if a candidate pretends to know it. Keep a positive spirit: A cheerful and optimistic attitude can go a long way. Their logic is that by being proactive they will somehow benefit from lowered expectations. Nothing can be further from the truth. It focuses attention on shortcomings. More generally, if you do not believe in yourself, you cannot expect others to believe in you. Appearance: Most software companies have a relaxed dress-code, and new grad- uates may wonder if they will look foolish by overdressing.
The damage done when you are too casual is greater than the minor embarrassment you may feel at being overdressed. It is always a good idea to err on the side of caution and dress formally for your interviews. At the minimum, be clean and well-groomed. Be aware of your body language: Think of a friend or coworker slouched all the time or absentmindedly doing things that may offend others.
Work on your posture, eye contact and handshake, and remember to smile. Keep money and perks out of the interview: Money is a big element in any job but it is best left discussed with the HR division after an offer is made.
The same is true for vacation time, day care support, and funding for conference travel. Strategies For A Great Interview Stress interviews Some companies, primarily in the finance industry, make a practice of having one of the interviewers create a stressful situation for the candidate.
The stress may be injected technically, e. The goal is to see how a candidate reacts to such situations—does he fall apart, become belligerent, or get swayed easily. The guidelines in the previous section should help you through a stress interview. Bear in mind you will not know a priori if a particular interviewer will be conducting a stress interview. Learning from bad outcomes The reality is that not every interview results in a job offer.
There are many reasons for not getting a particular job. Some are technical: you may have missed that key flash of insight, e. If this is the case, go back and solve that problem, as well as related problems. You can fail an interview for nontechnical reasons, e. The company may have decided not to hire in your area, or another candidate with similar ability but more relevant experience was hired. You will not get any feedback from a bad outcome, so it is your responsibility to try and piece together the causes.
Negotiating an offer An offer is not an offer till it is on paper, with all the details filled in. All offers are negotiable. When negotiating, remember there is nothing to be gained, and much to lose, by being rude.
Being firm is not the same as being rude. To get the best possible offer, get multiple offers, and be flexible about the form of your compensation.
For example, base salary is less flexible than stock options, sign- on bonus, relocation expenses, and Immigration and Naturalization Service INS filing costs. Otherwise the recruiter will simply come back with a small increase in the sign-on bonus and claim to have met your request. Your HR contact is a professional negotiator, whose fiduciary duty is to the com- pany. This is what recruiters ElementsOfProgrammingInterviews.
Strategies For A Great Interview 17 themselves are evaluated on internally. The Wikipedia article on negotiation lays bare many tricks we have seen recruiters employ. One suggestion: stick to email, where it is harder for someone to paint you into a corner.
If you are asked for something such as a copy of a competing offer , get something in return. Often it is better to bypass the HR contact and speak directly with the hiring manager. At the end of the day, remember your long term career is what counts, and joining a company that has a brighter future social-mobile vs. In this chapter we review practices that help interviewers identify a top hire.
We strongly recommend interviewees read it—knowing what an interviewer is looking for will help you present yourself better and increase the likelihood of a successful outcome. For someone at the beginning of their career, interviewing may feel like a huge responsibility. Hiring a bad candidate is expensive for the organization, not just because the hire is unproductive, but also because he is a drain on the productivity of his mentors and managers, and sets a bad example. Firing someone is extremely painful as well as bad for to the morale of the team.
On the other hand, discarding good candidates is problematic for a rapidly growing organization. Objective The ultimate goal of any interview is to determine the odds that a candidate will be a successful employee of the company. The ideal candidate is smart, dedicated, articulate, collegial, and gets things done quickly, both as an individual and in a team.
Ideally, your interviews should be designed such that a good candidate scores 1. One mistake, frequently made by novice interviewers, is to be indecisive.
Unless the candidate walks on water or completely disappoints, the interviewer tries not to make a decision and scores the candidate somewhere in the middle. This means that the interview was a wasted effort. A secondary objective of the interview process is to turn the candidate into a brand ambassador for the recruiting organization. Even if a candidate is not a good fit for the organization, he may know others who would be.
It is important for the candidate to have an overall positive experience during the process. Conducting An Interview 19 or insult the candidate over a mistake he made, but such behavior is depressingly common.
Outside of a stress interview, the interviewer should work on making the candidate feel positively about the experience, and, by extension, the position and the company. What to ask One important question you should ask yourself as an interviewer is how much training time your work environment allows. For a startup it is important that a new hire is productive from the first week, whereas a larger organization can budget for several months of training.
Consequently, in a startup it is important to test the candidate on the specific technologies that he will use, in addition to his general abilities. For a larger organization, it is reasonable not to emphasize domain knowledge and instead test candidates on data structures, algorithms, system design skills, and problem solving techniques. The justification for this is as follows. Algorithms, data structures, and system design underlie all software.
It is often hidden in library calls. However, such code is usually the crucial component in terms of performance and correctness, and often serves to differentiate products. Furthermore, platforms and programming languages change quickly but a firm grasp of data structures, algo- rithms, and system design principles, will always be a foundational part of any successful software endeavor.
Finally, many of the most successful software compa- nies have hired based on ability and potential rather than experience or knowledge of specifics, underlying the effectiveness of this approach to selecting candidates. Most big organizations have a structured interview process where designated interviewers are responsible for probing specific areas. For example, you may be asked to evaluate the candidate on their coding skills, algorithm knowledge, critical thinking, or the ability to design complex systems.
This book gives interviewers access to a fairly large collection of problems to choose from. When selecting a problem keep the following in mind: No single point of failure—if you are going to ask just one question, you should not pick a problem where the candidate passes the interview if and only if he gets one particular insight.
The best candidate may miss a simple insight, and a mediocre candidate may stumble across the right idea. There should be at least two or three opportunities for the candidates to redeem themselves. For example, problems that can be solved by dynamic programming can almost always be solved through a greedy algorithm that is fast but suboptimum or a brute-force algorithm that is slow but optimum.
In such cases, even if the candidate cannot get the key insight, he can still demonstrate some problem solving abilities. Problem 6. Multiple possible solutions—if a given problem has multiple solutions, the chances of a good candidate coming up with a solution increases. It also gives the interviewer more freedom to steer the candidate. A great candidate may finish ElementsOfProgrammingInterviews.
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