Skip to content

For employers Sign in

Make and follow sheets.Sign in

Problems

249 problems

Has video Premium only Reset

Array447 String249 Hash Table190 Math173 Database113 Sorting100 Simulation93 Counting70 Two Pointers70 Bit Manipulation54 Greedy51 Matrix41 Tree40 Depth-First Search39 Binary Tree37 All topics

Easy · 249 results

Sign in to see which of these you have solved.Sign in

TitleSolutionAcceptDifficultyTopics

13. Roman to IntegerVideo

Solution67.0%Easy

Hash Table, Math +1· 36 companies

14. Longest Common PrefixVideo

Solution48.6%Easy

String, Trie· 60 companies

20. Valid ParenthesesVideo

Solution45.2%Easy

Stack, String· 113 companies

28. Find the Index of the First Occurrence in a StringVideo

Solution47.0%Easy

String, String Matching +1· 16 companies

58. Length of Last WordVideo

Solution59.7%Easy

String· 7 companies

67. Add BinaryVideo

Solution58.4%Easy

Bit Manipulation, Math +2· 17 companies

125. Valid PalindromeVideo

Solution54.2%Easy

String, Two Pointers· 39 companies

168. Excel Sheet Column TitleVideo

Solution47.9%Easy

Math, String· 10 companies

171. Excel Sheet Column NumberVideo

Solution68.6%Easy

Math, String· 9 companies

205. Isomorphic StringsVideo

Solution48.8%Easy

Hash Table, String· 15 companies

242. Valid AnagramVideo

Solution68.5%Easy

Hash Table, Sorting +1· 40 companies

243. Shortest Word DistanceVideoPremium

Solution66.3%Easy

Array, String· 8 companies

246. Strobogrammatic NumberVideoPremium

Solution47.6%Easy

Hash Table, String +1· 2 companies

257. Binary Tree PathsVideo

Solution69.5%Easy

Backtracking, Binary Tree +3· 8 companies

266. Palindrome PermutationVideoPremium

Solution68.6%Easy

Bit Manipulation, Hash Table +1· 5 companies

290. Word PatternVideo

Solution44.5%Easy

Hash Table, String· 9 companies

293. Flip GameVideoPremium

Solution64.8%Easy

String· 1 company

344. Reverse StringVideo

Solution81.2%Easy

String, Two Pointers· 16 companies

345. Reverse Vowels of a StringVideo

Solution62.1%Easy

String, Two Pointers· 13 companies

383. Ransom NoteVideo

Solution66.3%Easy

Counting, Hash Table +1· 14 companies

387. First Unique Character in a StringVideo

Solution66.4%Easy

Counting, Hash Table +2· 25 companies

389. Find the DifferenceVideo

Solution60.8%Easy

Bit Manipulation, Hash Table +2· 6 companies

392. Is SubsequenceVideo

Solution49.5%Easy

Dynamic Programming, String +1· 16 companies

408. Valid Word AbbreviationVideoPremium

Solution37.0%Easy

String, Two Pointers· 7 companies

409. Longest PalindromeVideo

Solution55.9%Easy

Greedy, Hash Table +1· 8 companies

412. Fizz BuzzVideo

Solution75.9%Easy

Math, Simulation +1· 18 companies

415. Add StringsVideo

Solution52.1%Easy

Math, Simulation +1· 14 companies

434. Number of Segments in a StringVideo

Solution37.6%Easy

String· 3 companies

459. Repeated Substring PatternVideo

Solution48.6%Easy

String, String Matching· 9 companies

482. License Key FormattingVideo

Solution46.4%Easy

String· 1 company

500. Keyboard RowVideo

Solution74.3%Easy

Array, Hash Table +1· 4 companies

520. Detect CapitalVideo

Solution56.8%Easy

String· 4 companies

521. Longest Uncommon Subsequence IVideo

Solution62.7%Easy

String· 2 companies

541. Reverse String IIVideo

Solution54.7%Easy

String, Two Pointers· 7 companies

551. Student Attendance Record IVideo

Solution50.1%Easy

String· 3 companies

557. Reverse Words in a String IIIVideo

Solution84.0%Easy

String, Two Pointers· 7 companies

599. Minimum Index Sum of Two ListsVideo

Solution60.8%Easy

Array, Hash Table +1· 4 companies

604. Design Compressed String IteratorVideoPremium

Solution40.5%Easy

Array, Design +2· 1 company

657. Robot Return to OriginVideo

Solution78.0%Easy

Simulation, String· 5 companies

680. Valid Palindrome IIVideo

Solution44.7%Easy

Greedy, String +1· 16 companies

696. Count Binary SubstringsVideo

Solution70.3%Easy

String, Two Pointers· 18 companies

709. To Lower CaseVideo

Solution84.8%Easy

String· 3 companies

734. Sentence SimilarityVideoPremium

Solution44.5%Easy

Array, Hash Table +1· 1 company

748. Shortest Completing WordVideo

Solution63.5%Easy

Array, Hash Table +1· 1 company

771. Jewels and StonesVideo

Solution89.5%Easy

Hash Table, String· 6 companies

796. Rotate StringVideo

Solution66.6%Easy

String, String Matching· 12 companies

800. Similar RGB ColorVideoPremium

Solution68.6%Easy

Enumeration, Math +1· 1 company

804. Unique Morse Code WordsVideo

Solution83.6%Easy

Array, Hash Table +1· 3 companies

806. Number of Lines To Write StringVideo

Solution72.9%Easy

Array, String· 2 companies

819. Most Common WordVideo

Solution45.0%Easy

Array, Counting +2· 5 companies

Showing 1–50 of 249