Quant & Finance

Citadel interview questions

Grouped by topic, sorted Easy → Medium → Hard, then by LeetCode ID. Click a problem to open it on LeetCode; the chapter column links to the handbook chapter that covers it.

Problems
50
Easy
1
Medium
33
Hard
16
Mapped to chapter
27

Array

29 problems

Easy 1

346Moving Average from Data Streamalso at:Arista NetworksGoogleMeta Also at 2 moreQualcommTesla Easy—

Medium 18

11Container With Most Water★ also at:BloombergGoldman SachsAdobe Also at 24 moreAirtelAmazonAppleAtlassianByteDanceDream11FlipkartFreshworksGoogleGrowwIntelLyftMetaMicrosoftMyntraOktaOYOPayPalPaytmQualcommRazorpaySAPTeslaVMware MediumChapter
46Permutationsalso at:BloombergAdobeAmazon Also at 12 moreArista NetworksByteDanceCiscoeBayEpic SystemsGoogleGrowwMetaMicrosoftQualcommVMwareZomato MediumChapter
79Word Search★ also at:BloombergMorgan StanleyAdobe Also at 17 moreAmazonArista NetworksAtlassianByteDanceCiscoEpic SystemsFreshworksGoogleLyftMetaMicrosoftNetflixPayPalPaytmSnapUberVMware MediumChapter
122Best Time to Buy and Sell Stock IIalso at:AdobeAmazonApple Also at 7 moreGoogleGrowwMetaMicrosoftNaviPaytmToast Medium—
198House Robber★ also at:BloombergAdobeAirbnb Also at 24 moreAmazonByteDanceCars24CiscoCleartripCure.fitDatabricksDatadogeBayExpediaFlipkartGoogleIntuitMetaMicrosoftNianticNVIDIAOYOPayPalPhonePeSamsaraTeslaWalmart Global TechZoom MediumChapter
200Number of Islands★ also at:BloombergGoldman SachsAdobe Also at 43 moreAmazonAMDAppleAutodeskByteDanceCapital OneCiscoCloudflareCREDCrowdStrikeDocuSignDoorDashDropboxeBayFlipkartGoogleIntelIntuitLinkedInLyftMeeshoMetaMicrosoftOktaOlaPayPalPhonePePinterestQualcommRedditSAPSnapSplunkSpotifyTargetTeslaToastUberUrban CompanyVMwareWalmart Global TechZohoZomato MediumChapter
221Maximal Squarealso at:AdobeAirbnbAmazon Also at 10 moreFlipkartGoogleMicrosoftOYOPayPalPhonePeSAPVMwareWiseZomato Medium—
240Search a 2D Matrix IIalso at:BloombergAdobeAirtel Also at 11 moreAmazonByteDanceeBayGoogleInMobiMicrosoftOlaOYOPayPalSnapZomato Medium—
256Paint Housealso at:AmazonLinkedIn Medium—
300Longest Increasing Subsequence★ also at:BloombergMorgan StanleyAdobe Also at 12 moreAmazonAtlassianeBayFreshworksGoogleIntuitLINEMetaMicrosoftNVIDIAPayPalVMware MediumChapter
380Insert Delete GetRandom O(1)also at:BloombergAdobeAmazon Also at 20 moreAppleCars24CiscoDocuSignDoorDashGoogleIntuitLinkedInMicrosoftNetflixOktaOYORobloxSamsaraSnapTwilioUberVMwareX (Twitter)Yelp MediumChapter
622Design Circular Queuealso at:AmazonAppleCloudflare Also at 8 moreCoinbaseDatadogGoogleIntuitMicrosoftQualcommSplunkTesla MediumChapter
735Asteroid Collisionalso at:BloombergAmazonByteDance Also at 15 moreDoorDashDream11eBayFlipkartGoogleJuspayLyftMeeshoMetaMicrosoftMyntraNaviOpenAIPayPalPhonePe Medium—
740Delete and Earnalso at:Morgan StanleyMeesho MediumChapter
875Koko Eating Bananasalso at:BloombergGoldman SachsAdobe Also at 16 moreAmazonAtlassianAutodeskDoorDashFlipkartGoogleMetaMicrosoftNetflixNykaaOYOPayPalPhonePeSamsaraSwiggyZoom MediumChapter
974Subarray Sums Divisible by Kalso at:AmazonByteDanceGoogle Also at 2 moreMicrosoftTwilio MediumChapter
994Rotting Oranges★ also at:BloombergAdobeAmazon Also at 23 moreChimeCleartripDoorDashDream11eBayFlipkartGoogleIntuitLinkedInMetaMicrosoftMyntraOpenAIOYOPayPalPhonePeRakutenRobloxSalesforceUberUrban CompanyZohoZoom MediumChapter
2044Count Number of Maximum Bitwise-OR SubsetsMedium—

Hard 10

42Trapping Rain Wateralso at:BloombergGoldman SachsAdobe Also at 34 moreAirbnbAmazonAtlassianByteDanceCrowdStrikeDocuSigneBayFlipkartGoogleGrowwInMobiIntelIntuitLyftMetaMicrosoftMyntraNaviNVIDIAOpenAIPayPalPaytmPhonePeQualcommRakutenRobloxSAPSnowflakeSwiggyTeslaUrban CompanyWalmart Global TechX (Twitter)Zoho HardChapter
51N-Queens★ also at:BloombergAdobeAmazon Also at 10 moreByteDanceeBayFreshworksGoogleMetaMicrosoftOlaTiger AnalyticsZohoZoom HardChapter
188Best Time to Buy and Sell Stock IValso at:Groww Hard—
239Sliding Window Maximum★ also at:BloombergJPMorganAdobe Also at 20 moreAmazonAutodeskByteDanceCiscoDeliverooDoorDashExpediaGoogleJuspayLINELyftMetaMicrosoftMongoDBNVIDIAOYOPhonePeRobloxVMwareWayfair HardChapter
329Longest Increasing Path in a Matrixalso at:AdobeAmazonApple Also at 9 moreByteDanceDoorDashDuolingoEpic SystemsGoogleMetaMicrosoftPhonePeSnap HardChapter
381Insert Delete GetRandom O(1) - Duplicates allowedalso at:DiscordLinkedInMeta Also at 2 moreOktaYelp Hard—
759Employee Free Timealso at:AirbnbGoogleIntuit Also at 2 moreMicrosoftRoblox Hard—
815Bus Routesalso at:BloombergAmazonGoogle Also at 5 moreInfo Edge (Naukri)PhonePePinterestSnapUber Hard—
2050Parallel Courses IIIalso at:Two SigmaAmazonMicrosoft Also at 4 moreNaviSnapSnowflakeStripe Hard—
2361Minimum Costs Using the Train LineHard—

Depth-First Search

4 problems

Medium 3

207Course Schedule★ also at:AmazonAppleByteDance Also at 22 moreCars24CloudflareCrowdStrikeDoorDasheBayFlipkartGoogleIntuitMetaMicrosoftPayPalRobloxSalesforceSnapSnowflakeSwiggyTargetToastUberWalmart Global TechYelpZomato MediumChapter
210Course Schedule IIalso at:BloombergAmazonApple Also at 24 moreArista NetworksCars24CleartripCoinbaseCure.fitDatabricksDoorDashFlipkartGoogleIntuitLinkedInMetaMicrosoftMongoDBNetflixPalantirQualcommRobloxSalesforceSnapSnowflakeTeslaUberUrban Company MediumChapter
310Minimum Height Treesalso at:Microsoft MediumChapter

Hard 1

1203Sort Items by Groups Respecting DependenciesHard—

Dynamic Programming

3 problems

Medium 3

688Knight Probability in ChessboardMedium—
2466Count Ways To Build Good Stringsalso at:MetaMicrosoft Medium—
2533Number of Good Binary StringsMedium—

Hash Table

3 problems

Medium 2

12Integer to Romanalso at:BloombergAdobeAmazon Also at 9 moreAMDAtlassianDocuSignDoorDashGoogleMetaMicrosoftSwiggyX (Twitter) Medium—
208Implement Trie (Prefix Tree)★ also at:BloombergAmazonApple Also at 10 moreBlockDocuSignDoorDasheBayGoogleMetaMicrosoftMongoDBRobloxX (Twitter) MediumChapter

Hard 1

460LFU Cache★ also at:AdobeAmazonDiscord Also at 11 moreDoorDashExpediaGoogleLinkedInMicrosoftPayPalRipplingSalesforceVMwareWalmart Global TechZomato HardChapter

Math

3 problems

Medium 2

50Pow(x, n)★ also at:BloombergAdobeAmazon Also at 7 moreCiscoeBayGoogleMetaMicrosoftQualcommVMware MediumChapter
279Perfect Squaresalso at:AdobeAmazoneBay Also at 3 moreGoogleLyftRevolut Medium—

Hard 1

224Basic Calculator★ also at:BloombergAdobeAmazon Also at 5 moreDoorDashGoogleMetaMicrosoftTesla HardChapter

Misc

8 problems

Medium 5

98Validate Binary Search Tree★ also at:BloombergAdobeAmazon Also at 7 moreByteDanceeBayGoogleMetaMicrosoftOYOVMware MediumChapter
103Binary Tree Zigzag Level Order Traversalalso at:AmazonByteDanceeBay Also at 5 moreGoogleIntuitMicrosoftOlaZoom MediumChapter
116Populating Next Right Pointers in Each Nodealso at:BloombergAmazonGoogle Also at 4 moreMetaMicrosoftVMwareWise MediumChapter
117Populating Next Right Pointers in Each Node IIalso at:Meta Medium—
647Palindromic Substringsalso at:AdobeAmazonArista Networks Also at 7 moreCapital OneCiscoEpic SystemsMetaMicrosoftPayPalVMware MediumChapter

Hard 3

10Regular Expression Matchingalso at:BloombergAdobeAirbnb Also at 11 moreAmazonAppleByteDanceeBayGoogleLyftMetaMicrosoftPhonePeX (Twitter)Zoho Hard—
489Robot Room Cleaneralso at:Two SigmaLinkedInMeta Hard—
2484Count Palindromic Subsequencesalso at:PhonePeVisa Hard—