Coding interview: Difference between revisions

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A '''coding interview''', '''technical interview''', '''programming interview''' or '''Microsoft interview''' is a technical problem-based [[job interview]] technique to assess potential employees. The technique was pioneered by [[Microsoft]], and subsequently developed by other large technology companies including [[Amazon.com|Amazon]], [[Facebook]], and [[Google]].<ref>[http://ifdefined.com/blog/post/Google-interview.aspx Applicants blog] after Google interview. {{Webarchive|url=https://web.archive.org/web/20110313021040/http://ifdefined.com/blog/post/Google-interview.aspx |date=March 13, 2011 }}</ref><ref>[https://www.npr.org/templates/story/story.php?storyId=1405340 Job Interviews Get Creative, NPR 2003]. Retrieved from the World Wide Web on January 16, 2006.</ref> Coding interviews test candidates' technical knowledge, coding ability, problem solving skills, and creativity, typically on a [[whiteboard]]. Candidates usually have a degree in [[computer science]], [[information science]], [[computer engineering]] or [[electrical engineering]], and are asked to solve [[Mathematical programming|programming]] problems, [[algorithms]], or [[puzzle]]s.<ref>{{citation |title=Programming Interviews Exposed: Secrets to Landing Your Next Job |author=John Mongan |edition=2nd |isbn=978-0-470-12167-2 |publisher=Wrox |url-access=registration |url=https://archive.org/details/programminginter00mong_0 }}</ref><ref name=ctci>{{Cite book|title=[[Cracking the Coding Interview|Cracking the coding interview : 189 programming questions and solutions]]|last=McDowell|year=2015|first=Gayle Laakmann|author-link=Gayle Laakmann McDowell|isbn=978-0-9847828-5-7|edition=6th|___location=Palo Alto, CA|oclc=913477191}}</ref> Coding interviews are typically conducted in-person or virtually.

==Innovation==

The Microsoft's Interviewinterview style was a pioneerdistinctive in that it was aboutconcerned technical knowledge, problem solving and creativity as opposed to the [[Job interview#Behavioral interview questions|goal and weaknesses interviews]] most companies used at the time. Initially based on [[Bill Gates]]'s obsession with puzzles, many of the puzzles presented during interviews started off being [[Fermi problem]]s, or sometimes logic problems, and have eventually transitioned over the years into questions relevant to programming:<ref>{{cite book | last = Poundstone | author-link = William Poundstone | first = William | title = How Would You Move Mount Fuji | ___location = Boston | publisher = [[Little, Brown and Company]] | year = 2003 | pages = [https://archive.org/details/howwouldyoumovem00poun/page/50 50–90] | isbn = 0-316-91916-0 | url = https://archive.org/details/howwouldyoumovem00poun/page/50 }}</ref>

<blockquote>Puzzles test competitive edge as well as intelligence. Like business or football, a logic puzzle divides the world into winners and losers. You either get the answer, or you don't... Winning has to matter.<ref>Poundstone, page 62.</ref></blockquote>

=== Example interview questions ===

The questions asked during thea Microsoftcoding Interviewinterview are crafted to determine a candidate's problem solving, coding and design abilities. Eccentric questions (such as ''Which of the fifty states would you remove?'') test a candidate's ability to come to a decision and articulate it.<ref>Poundstone, page 67.</ref> Candidates answering questions should consider the use of technology in the present and future, and [[user scenarios]]. Some questions involve projects that the candidate has worked on in the past.

TheA Microsoftcoding Interviewinterview is intended to seek out creative thinkers and those who can adapt their solutions to rapidly changing and dynamic scenarios.{{cn}}

Typical questions that a candidate might be asked to answer during the second-round interview include:{{cn}}

* What is the cosine law and how do you use this in real life situations?

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* Shift all elements of a circular array by k bytes, using no extra memory.

===Programming language===

If the interviewing position has specific [[programming language]] requirements, the candidate is expected to know those languages and solve the questions with it. If the interview is for general programming or development position, a thorough knowledge of one mainstream language such as [[C (programming language)|C]], [[C++]], [[C Sharp (programming language)|C#]], or [[Java (programming language)|Java]] may be enough to get by.{{Citation needed|date=February 2011}} An interviewer may also allow use of other popular languages, such as [[JavaScript]], [[PHP]], or [[Perl]].

====Manhole cover question====

[[File:Open Manhole and Cover Mid-City New Orleans.jpg|thumb|A round manhole and its cover]]

TheMicrosoft popularized the question of why [[manhole covers]] are typically round (in some countries) was made famous by [[Microsoft]] when they began asking it as a job- interview question.<ref name="Microsoft Puzzle Book">{{cite book| last = Poundstone| first = William| title = How Would You Move Mount Fuji? Microsoft's Cult of the Puzzle – How the World's Smartest Company Selects the Most Creative Thinkers| publisher = Little, Brown| year = 2003| isbn = 0-316-91916-0| url = https://archive.org/details/howwouldyoumovem00poun}}</ref><ref>{{cite web|last=Davis |first=Jim |url=http://www.joblossguide.com/2009/02/why-are-manhole-covers-round_10.html |title=Why Are Manhole Covers Round? |publisher=Joblossguide.com |date=2009-02-10 |access-date=2011-04-08 |url-status=dead |archive-url=https://web.archive.org/web/20110612064454/http://www.joblossguide.com/2009/02/why-are-manhole-covers-round_10.html |archive-date=June 12, 2011 |df=mdy }}</ref> Originally meant as a psychological assessment of how one approaches a question with more than one correct answer, the problem has produced a number of alternative explanations, from the [[tautology (rhetoric)|tautological]] ("Manhole covers are round because manholes are round.")<ref name="Microsoft Puzzle Book" /> to the philosophical.

Reasons for the shape include:

* A round manhole cover cannot fall through its circular opening, whereas a square manhole cover may fall in if it were inserted diagonally in the hole. The existence of a "lip" holding up the lid means that the underlying hole is smaller than the cover, so that other shapes might suffice. (A [[Reuleaux triangle]] or other [[curve of constant width]] would also serve this purpose, but round covers are much easier to manufacture.)

* Round tubes are the strongest and most material-efficient shape against the compression of the earth around them, and so it is natural that the cover of a round tube assume a circular shape.

* A round manhole cover has a smaller surface than a square one, thus less material is needed to cast the manhole cover, meaning lower cost.

* The bearing surfaces of manhole frames and covers are machined to assure flatness and prevent them from becoming dislodged by traffic. Round castings are much easier to machine using a lathe.

* Circular covers do not need to be rotated to align with the manhole.

* A round manhole cover can be more easily moved by being rolled.

* A round manhole cover can be easily locked in place with a quarter turn (as is done in countries like France), which makes them hard to open without a special tool. Lockable covers do not have to be made as heavy, because traffic passing over them cannot lift them up by suction.

The practice of asking these sorts of so-called [[lateral thinking]] questions was later formally discouraged at Microsoft.

The practice of asking these sorts of so-called [[lateral thinking]] questions was later formally discouraged at Microsoft.{{cn}}

===Interview resources===

Microsoft provides a list of suggested reading to prepare for its interview. Notable examples include:{{citation needed|date=January 2020}}<!-- A source should indicate that Microsoft has listed these books, otherwise this section should be reevaluated-->

===Programming language===

* [[Steve McConnell|McConnell, Steve]] (2004) ''[[Code Complete]]'' ([[Microsoft Press]], 2nd ed.) {{ISBN|978-0-7356-1967-8}}

If the interviewing position has specific [[programming language]] requirements, the candidate is expected to know those languages and solve the questions with it. If the interview is for general programming or development position, a thorough knowledge of one mainstream language such as [[C (programming language)|C]], [[C++]], [[C Sharp (programming language)|C#]], or [[Java (programming language)|Java]] may be enough to get by.{{Citation needed|date=February 2011}} An interviewer may also allow use of other popular languages, such as [[JavaScript]], [[PHP]], or [[Perl]].{{cn}}

* [[Bill Gates|Gates, Bill]], Hemingway, Collins (1999) ''[[Business @ the Speed of Thought]]'' {{ISBN missing}}

* Gates, Bill (1995) ''[[The Road Ahead (Bill Gates book)|The Road Ahead]]'' {{ISBN missing}}

* [[Frederick P. Brooks, Jr.|Brooks Jr., Frederick P.]] ''[[Mythical Man-Month]]'', (Addison-Wesley, Anniversary Edition), 1995. {{ISBN |978-0-201-83595-3}}

* [[Donald Knuth|Knuth, Donald]] (1968-) ''[[The Art of Computer Programming]]'', (Addison-Wesley). {{ISBN|0-201-03801-3}}

==References==