LeetCode: Difference between revisions

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{{short description|Online platform for coding interview preparation}}

{{Infobox companywebsite

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| name = Leetcode

{{Article for deletion/dated|page=Leetcode|timestamp=20230810044029|year=2023|month=August|day=10|substed=yes}}

| logo = [[File:LeetCode Logo black with text.svg|250px]]

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{{Advertisement|date=June 2023}}

{{Infobox company

| name = Leetcode

| logo = Leetcode.svg

| type = [[Privately held company|Private]]

| industry = Software

| logoowner = Leetcode.svg LLC

| founder = Vinston Tang

| founded = 7 August 2015

| founder = VinstonWinston Tang

| location_city = [[Palo Alto]], [[California]]

| location_country = [[United States|US]]

| key_people = Hercy Chang (CEO)

| num_employees = 264 (2025)<ref>[https://leadiq.com/c/leetcode/5a6861465700003b015b2278/employee-directory LeetCode Employee Directory, Headcount &amp; Staff] ''LeadIQ''</ref>

| website = https://leetcode.com/

|revenue = US$8 million<ref>[https://siliconvalleyjournals.com/company/leetcode LeetCode: Contact Details, Revenue, Funding, Employees and Company Profile]

''Silicon Valley Journal''</ref> (2024)

| website = https://* {{official website|2=leetcode.com/}}

* {{official website||2=leetcode.cn}} (in Chinese)

}}

'''LeetCode''' is an [[online discussion platform|online platform]] offeringfor [[Coding interview|coding challenges and interview]] preparation resources for software engineers and developers. The serviceplatform provides coding and algorithmic problems, enablingintended for users to practice [[Software development|coding and improve their problem-solving abilities]].<ref name=nytimes2023/> LeetCode has gained popularity among job seekers in the [[software industry]] and coding enthusiasts as a resource for technical interviews and coding competitions.<ref name=":0nytimes2023">{{Cite web |last=Ansari |first=Tasmia |date=2022-11-17 |title=The Ultimate Guide to Cracking Data Science Interviews |url=https://analyticsindiamag.com/the-ultimate-guide-to-cracking-data-science-interviews/ |access-date=2023-06-10 |website=Analytics India Magazine |language=en-US}}</ref><ref>{{Cite web |last=Kolakowski |first=Nick |date=2022-12-08 |title=Which Programming Languages Are Growing? |url=https://www.dice.com/career-advice/which-programming-languages-are-growing |access-date=2023-06-10 |website=Dice Insights |language=en}}</ref><ref name=nytimes2023>{{Cite news |last=Singer |first=Natasha |date=2023-04-05 |title=For Lower-Income Students, Big Tech Internships Can Be Hard to Get |language=en |url=https://www.nytimes.com/2023/04/05/business/tech-internship-application-grind.html |access-date=2023-08-09 |work=The New York Times |language=en |quote=To gear up for the assessments, many students practice their skills on LeetCode, a free test prep site that offers coding and algorithmic problems, along with detailed solutions. The site also offers premium services. For $35 a month, it gives members access to specific problems that companies like Amazon, Google and Microsoft previously used — and some continue to use — to assess applicants. To keep the questions up-to-date, the test prep service said, it regularly surveys members applying for tech positions.}}</ref><ref name=":0">{{Cite web |last=Ansari |first=Tasmia |date=2022-11-17 |title=The Ultimate Guide to Cracking Data Science Interviews |url=https://analyticsindiamag.com/the-ultimate-guide-to-cracking-data-science-interviews/ |access-date=2023-06-10 |website=Analytics India Magazine |language=en-US}}</ref><ref>{{Cite web |last=Kolakowski |first=Nick |date=2022-12-08 |title=Which Programming Languages Are Growing? |url=https://www.dice.com/career-advice/which-programming-languages-are-growing |access-date=2023-06-10 |website=Dice Insights |language=en}}</ref><ref name="dummies">{{Cite book |last=Sonmez |first=John |url=https://books.google.com/books?id=rEOvDwAAQBAJ&newbks=0&printsec=frontcover&pg=PA108&dq=LeetCode&hlpg=enPA108 |title=Programming Interviews For Dummies |last2=Butow |first2=Eric |date=2019-09-11 |publisher=John Wiley & Sons |isbn=978-1-119-56506-2 |language=en |quote=LeetCode is also a popular site for programmers who want to get up to speed.}}</ref><ref>{{Citation |last=Harper |first=Jocelyn |title=Interview Insight: How to Get the Job |date=2023 |url=https://doi.org/10.1007/978-1-4842-8783-5_4 |work=A Software Engineer’sEngineer's Guide to Seniority: A Guide to Technical Leadership |pages=19–28 |editor-last=Harper |editor-first=Jocelyn |url=https://doi.org/10.1007/978-1-4842-8783-5_4 |access-date=2023-08-11 |place=Berkeley, CA |publisher=Apress |language=en |doi=10.1007/978-1-4842-8783-5_4 |isbn=978-1-4842-8783-5 |quote=LeetCode is a platform that specializes in algorithm questions ranked from “Easy” to “Hard” based on the complexity of the subject and solution. They also have a forum where people share what interview questions they encountered in phone screens and on-site interviews to share with the larger public and to help software engineers prepare. I have been fortunate that the only time that I encountered a LeetCode problem during a screening process was for Amazon. ... On this last interviewing journey, I found myself enjoying practicing algorithm coding questions because I found alternative resources to LeetCode.|url-access=subscription }}</ref> As of 2025, the website has 26.3 million monthly visitors.<ref>[https://www.similarweb.com/website/leetcode.com leetcode.com Traffic analytics, ranking & audience (May 2025)] ''[[Similarweb]]''</ref>

== Features ==

LeetCode offers both free and premium access options. While free users have access to a limited number of questions, premium users gain access to over 2500 algorithmically and user-generatedadditional questions. Thesepreviously questionsused arein categorizedinterviews intoat easy,large medium,tech and hard difficulty levels, allowing users to select challenges based on their proficiencycompanies.<ref>{{Cite web |titlename=LeetCode - The World's Leading Online Programming Learning Platform |url=https:nytimes2023//leetcode.com/ |access-date=2023-06-21 |website=leetcode.com}}</ref> Users can also tag questions to facilitate searchability and provide assistance to others in finding relevant practice problems. The performance of users' solutions is evaluated based on response[[Time_complexity|execution speed]] and solution[[Memory management|memory efficiencyusage]], and is ranked against other submissions in the LeetCode database.<ref name="xingBI">{{Cite web |last=Xing |first=Jessica |title=Here's what job seekers need to know about LeetCode, the coding-skills platform millions of developers use to ace the notoriously difficult technical interviews at firms such as Apple, Amazon, and Google |url=https://www.businessinsider.com/leetcode-coding-test-apple-amazon-google-technical-interview-prep-job-2021-11 |access-date=2023-06-21 |website=Business Insider |language=en-US}}</ref>

Additionally, LeetCode provides its users with mock interviews and online assessments. LeetCode hosts weekly and biweekly contests, each having 4 problems.<ref name="dummies" /><ref name="LeetCodeWebsite">{{Cite web |title=LeetCode - The World's Leading Online Programming Learning Platform |url=https://leetcode.com/ |access-date=2023-10-10 |website=leetcode.com}}</ref> After participating in a contest for the first time, one gets assigned a ranking, which can be found in their profile.<ref>{{Cite web |title=Contest |url=https://leetcode.com/contest/ |access-date=2023-10-10 |website=LeetCode |language=en}}</ref> LeetCode also provides its users with daily challenges, following UTC, with a lucky draw at the end of each month for those who stayed consistent for the month.<ref>{{Cite web |title=What is Daily LeetCoding Challenge?|url=https://leetcode.com/discuss/general-discussion/655704/ |access-date=2023-12-09 |website=leetcode.com}}</ref>

LeetCode supports multiple programming languages, including [[Java (programming language)|Java]], [[Python (programming language)|Python]], [[JavaScript]], and [[C (programming language)|C]].<ref>{{Cite journal |last=Nguyen |first=Nhan |last2=Nadi |first2=Sarah |date=2022-10-17 |title=An empirical evaluation of GitHub copilot's code suggestions |url=https://doi.org/10.1145/3524842.3528470 |journal=Proceedings of the 19th International Conference on Mining Software Repositories |series=MSR '22 |___location=New York, NY, USA |publisher=Association for Computing Machinery |pages=1–5 |doi=10.1145/3524842.3528470 |isbn=978-1-4503-9303-4 |quote=LeetCode questions come with test cases in various programming languages, ... (Python, Java, JavaScript, and C)|doi-access=free }}</ref> Users can practice coding in their preferred language and utilize flashcards to study and reinforce their knowledge. The platform features forums where users can engage in discussions related to challenging problems, the interview process, and share their interview experiences for the benefit of the community. LeetCode also hosts weekly and bi-weekly contests, some of which were sponsored by companies like [[Amazon (company)|Amazon]], [[Motorola]], and [[Bharti Airtel|Airtel]].<ref>{{Cite web |title=Contest - LeetCode |url=https://leetcode.com/contest/contest-for-motorola-testing/ |access-date=2023-06-21 |website=leetcode.com}}</ref> Contestants have the opportunity to earn badges and "LeetCoin" rewards by successfully solving contest questions.

LeetCode supports a wide range of programming languages, including [[Java (programming language)|Java]], [[Python (programming language)|Python]], [[JavaScript]], and [[C (programming language)|C]].<ref>{{Cite book |last=Nguyen |first=Nhan |title=Proceedings of the 19th International Conference on Mining Software Repositories |last2=Nadi |first2=Sarah |date=2022-10-17 |publisher=Association for Computing Machinery |isbn=978-1-4503-9303-4 |series=MSR '22 |___location=New York, NY, USA |pages=1–5 |chapter=An empirical evaluation of GitHub copilot's code suggestions |doi=10.1145/3524842.3528470 |quote=LeetCode questions come with test cases in various programming languages, ... (Python, Java, JavaScript, and C) |doi-access=free}}</ref> In September 2024, LeetCode China supports [[Huawei]]'s {{ill|Cangjie programming language|zh|仓颉编程语言}} for all problems.<ref>{{Cite web |title= |script-title=zh:编程刷题平台 LeetCode 力扣所有题目均已支持华为仓颉语言 |trans-title=All problems on the programming practice platform LeetCode are now supported in Huawei's Cangjie language |url=https://www.sohu.com/a/809062659_114760 |access-date=2024-12-03 |website=[[Sohu]]}}</ref>

== History ==

The platform features forums where users can engage in discussions related to problems, the interview process, and share their interview experiences.<ref name="dummies" />

LeetCode was founded by Winston Tang in 2011.{{Citation needed}} LeetCode was founded in [[Silicon Valley]].<ref>{{Cite book |last=吴江编著 |url=https://books.google.com/books?id=ENZqEAAAQBAJ&pg=PT9#v=onepage&q&f=false |title=高效制胜：程序员面试典型题解 |date=2021-07-01 |publisher=Beijing Book Co. Inc. |isbn=978-7-115-55198-6 |language=zh}}</ref>

== Types of problems ==

LeetCode expanded its operations to China in 2018 in response to surging demand.<ref name=yicai>{{Cite web |first=Liao |last= Shumin |title=IT Job Interview Prepper LeetCode Pockets USD10 Million From Lightspeed China |url=https://www.yicaiglobal.com/news/it-job-interview-prepper-leetcode-pockets-usd10-million-from-lightspeed-china |access-date=2023-08-16 |website=www.yicaiglobal.com |language=en}}</ref> In 2021, LeetCode secured its first round of funding, receiving a $10 million investment from [[Lightspeed China Partners]].<ref name=yicai/>

Every question on LeetCode has a particular category or tag. Some of the most common tags include [[Array_(data_structure)|arrays]], [[String_(computer_science)|strings]], [[Pointer_(computer_programming)|two pointer]]s, [[Stack_(abstract_data_type)|stack]]s, [[binary search]], sliding windows, [[linked list]]s, [[Tree_(data_structure)|trees]], [[trie]]s, [[backtracking]], [[Heap_(data_structure)|heap]]s, [[priority queue]]s, [[Graph_(abstract_data_type)|graph]]s, [[breadth-first search]], [[depth-first search]], [[dynamic programming]], [[greedy algorithm]]s, [[bit manipulation]], [[Database|database problems]], and math.<ref>{{Cite web |title=NeetCode.io |url=https://neetcode.io/roadmap |access-date=2023-10-10 |website=neetcode.io}}</ref>{{Better source needed|date=October 2023}} As of April 2025, LeetCode offers 3525 questions across its three levels of difficulty; with 873 questions categorized as easy, 1829 as medium, and 823 as hard.<ref name="LeetCodeWebsite" />{{Better source needed|date=June 2024}}

== History ==

LeetCode was founded in Silicon Valley in 2015 by Winston Tang.<ref>{{Cite web |title=Secretary of State |url=https://bizfileonline.sos.ca.gov/search/business |access-date=2024-03-21 |website=bizfileonline.sos.ca.gov}}</ref><ref name=":1">{{Cite web |last=Curry |first=Rachel |date=2024-06-24 |title=AI is shaping the fate of software engineers, but there is a new way to succeed |url=https://www.cnbc.com/2024/06/24/ai-shaping-fate-of-software-engineers-but-there-is-new-way-to-succeed.html |access-date=2024-06-26 |website=CNBC |language=en}}</ref> After moving to the US from Malaysia in 2005, Tang founded the company, citing his own experiences working at Amazon and Google as inspiration.<ref>{{Cite web |last=Tang |first=Winston |title=AI cannot replace software engineers—take it from someone who fought to become one and now helps others pursue the career |url=https://fortune.com/2024/07/30/ai-cannot-replace-software-engineers-or-threaten-their-careers/ |access-date=2024-07-31 |website=Fortune |language=en}}</ref><ref name=":1" />

LeetCode expanded its operations to China in 2018, inproviding responseChinese toproblems, surgingsolutions demandand forums on its Chinese website ''Likou'' ({{Zh|c=力扣|p=Lìkòu}}).<ref name="yicai">{{Cite web |firstlast=LiaoShumin |lastfirst= ShuminLiao |title=IT Job Interview Prepper LeetCode Pockets USD10 Million From Lightspeed China |url=https://www.yicaiglobal.com/news/it-job-interview-prepper-leetcode-pockets-usd10-million-from-lightspeed-china |access-date=2023-08-16 |website=www.yicaiglobal.com |language=en}}</ref> In 2021, LeetCode secured its first round of funding, receiving a $10 million investment from [[Lightspeed China Partners]].<ref name=yicai/>

== See also ==

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== References ==

<references />

[[Category:Educational websites]]

== External links ==

* {{Official website}}

[[Category:American educational websites]]

[[Category:Programming contests]]

[[Category:Computer science competitions]]

[[Category:Software developer communities]]

<references />{{compu-website-stub}}