LeetCode: Difference between revisions

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

{{Infobox companywebsite

| name = LeetCode

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

| logo =

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

| industry = Software

|owner = Leetcode LLC

| founder =

| founded = 7 August 2015

| key_people =

| founder = Winston Tang

| website = https://leetcode.com/

| 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>

|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]] for [[Coding interview|coding interview]] preparation. The serviceplatform provides coding and algorithmic problems intended for users to practice [[Software development|coding]].<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 |work=The New York Times |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 |last1last=Sonmez |first1first=John |url=https://books.google.com/books?id=rEOvDwAAQBAJ&dq=LeetCode&pg=PA108 |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>

'''LeetCode''' is an [[online discussion platform|online platform]] for coding interview preparation. The service provides coding and algorithmic problems intended for users to practice [[Software development|coding]].<ref name=nytimes2023/> LeetCode has gained popularity among job seekers and coding enthusiasts as a resource for technical interviews and coding competitions.<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=nytimes2023>{{Cite news |last=Singer |first=Natasha |date=2023-04-05 |title=For Lower-Income Students, Big Tech Internships Can Be Hard to Get |work=The New York Times |language=en |url=https://www.nytimes.com/2023/04/05/business/tech-internship-application-grind.html |access-date=2023-08-09 |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=dummies>{{Cite book |last1=Sonmez |first1=John |url=https://books.google.com/books?id=rEOvDwAAQBAJ&dq=LeetCode&pg=PA108 |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’s Guide to Seniority: A Guide to Technical Leadership |pages=19–28 |editor-last=Harper |editor-first=Jocelyn |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. }}</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 additional questions previously used in interviews at large tech companies.<ref name=nytimes2023/> The performance of users' solutions is evaluated based on response[[Time_complexity|execution speed]] and solution[[Memory efficiencymanagement|memory usage]], 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 contests are competitive events that provide a platform for coders around the world to test and enhance their algorithmic skills. LeetCode hosts weekly and bi-weekly contests, each having 4 problems to solve in 90 minutes. After you participate in a contest for the first time, you get assigned a ranking, which can be found in the profile. This rating is updated within 5 working days after the contest.

LeetCode supports multiplea wide range of programming languages, including [[Java (programming language)|Java]], [[Python (programming language)|Python]], [[JavaScript]], and [[C (programming language)|C]].<ref>{{Cite book |last1last=Nguyen |first1first=Nhan |last2=Nadi |first2=Sarah |title=Proceedings of the 19th International Conference on Mining Software Repositories |chapterlast2=AnNadi empirical|first2=Sarah evaluation|date=2022-10-17 of|publisher=Association GitHubfor copilot'sComputing code suggestionsMachinery |dateisbn=2022978-101-174503-9303-4 |series=MSR '22 |___location=New York, NY, USA |publisherpages=Association1–5 for|chapter=An Computingempirical Machineryevaluation |pages=1–5of GitHub copilot's code suggestions |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> TheIn platformSeptember features2024, forumsLeetCode whereChina userssupports can[[Huawei]]'s engage{{ill|Cangjie inprogramming discussionslanguage|zh|仓颉编程语言}} relatedfor toall challengingproblems.<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 interviewprogramming process,practice andplatform shareLeetCode theirare interviewnow experiencessupported in Huawei's Cangjie language |url=https://www.<refsohu.com/a/809062659_114760 name|access-date=dummies2024-12-03 |website=[[Sohu]]}}</ref>

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

== History ==

== Types of problems ==

LeetCode was founded in [[Silicon Valley]].<ref>{{Cite book |last=吴江编著 |url=https://books.google.com/books?id=ENZqEAAAQBAJ&pg=PT9 |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>

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 expanded its operations to China in 2018.<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/>

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, providing Chinese problems, solutions and 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}}