Problem set
Strings questions
142 matching · 44 easy · 71 medium · 27 hard
- 03Longest Substring Without Repeating CharactersMedium
- 05Longest Palindromic SubstringMedium
- 06Zigzag ConversionMedium
- 08String to Integer (atoi)Medium
- 10Regular Expression MatchingHard
- 12Integer to RomanMedium
- 13Roman to IntegerEasy
- 14Longest Common PrefixEasy
- 17Letter Combinations of a Phone NumberMedium
- 20Valid ParenthesesEasy
- 22Generate ParenthesesMedium
- 28Find the Index of the First Occurrence in a StringEasy
- 30Substring with Concatenation of All WordsHard
- 32Longest Valid ParenthesesHard
- 38Count and SayMedium
- 43Multiply StringsMedium
- 44Wildcard MatchingHard
- 49Group AnagramsMedium
- 58Length of Last WordEasy
- 65Valid NumberHard
- 67Add BinaryEasy
- 68Text JustificationHard
- 71Simplify PathMedium
- 72Edit DistanceMedium
- 76Minimum Window SubstringHard
- 87Scramble StringHard
- 91Decode WaysMedium
- 93Restore IP AddressesMedium
- 97Interleaving StringMedium
- 115Distinct SubsequencesHard
- 125Valid PalindromeEasy
- 126Word Ladder IIHard
- 127Word LadderHard
- 131Palindrome PartitioningMedium
- 132Palindrome Partitioning IIHard
- 139Word BreakMedium
- 140Word Break IIHard
- 151Reverse Words in a StringMedium
- 156Read N Characters Given Read4Easy
- 157Longest Substring with At Most Two Distinct CharactersMedium
- 159One Edit DistanceMedium
- 163Compare Version NumbersMedium
- 164Fraction to Recurring DecimalMedium
- 166Excel Sheet Column TitleEasy
- 168Excel Sheet Column NumberEasy
- 172Largest NumberMedium
- 173Repeated DNA SequencesMedium
- 185Isomorphic StringsEasy
- 188Implement Trie (Prefix Tree)Medium
- 191Design Add and Search Words Data StructureMedium
- 194Shortest PalindromeHard
- 204Basic CalculatorHard
- 207Basic Calculator IIMedium
- 222Valid AnagramEasy
- 223Shortest Word DistanceEasy
- 225Strobogrammatic NumberEasy
- 226Group Shifted StringsMedium
- 230Binary Tree PathsEasy
- 237Palindrome PermutationEasy
- 239Alien DictionaryHard
- 241Encode and Decode StringsMedium
- 242Integer to English WordsHard
- 249Expression Add OperatorsHard
- 256Word PatternEasy
- 259Serialize and Deserialize Binary TreeHard
- 261Bulls and CowsMedium
- 263Remove Invalid ParenthesesHard
- 271Remove Duplicate LettersMedium
- 283Palindrome PairsHard
- 287Longest Substring with At Most K Distinct CharactersMedium
- 291Reverse StringEasy
- 292Reverse Vowels of a StringEasy
- 319Ransom NoteEasy
- 322First Unique Character in a StringEasy
- 323Longest Absolute File PathMedium
- 325Is SubsequenceEasy
- 327Decode StringMedium
- 328Longest Substring with At Least K Repeating CharactersMedium
- 331Remove K DigitsMedium
- 336Valid Word AbbreviationEasy
- 337Longest PalindromeEasy
- 339Fizz BuzzEasy
- 342Add StringsEasy
- 347Longest Repeating Character ReplacementMedium
- 352Minimum Genetic MutationMedium
- 356Find All Anagrams in a StringMedium
- 359String CompressionMedium
- 369Repeated Substring PatternEasy
- 374Validate IP AddressMedium
- 376Concatenated WordsHard
- 394Longest Palindromic SubsequenceMedium
- 404Construct Binary Tree from StringMedium
- 406Minimum Time DifferenceMedium
- 408Reverse String IIEasy
- 414Next Greater Element IIIMedium
- 415Reverse Words in a String IIIEasy
- 419Permutation in StringMedium
- 422Delete Operation for Two StringsMedium
- 426Construct String from Binary TreeEasy
- 428Add Bold Tag in StringMedium
- 437Decode Ways IIHard
- 440Palindromic SubstringsMedium
- 441Replace WordsMedium
- 455Valid Palindrome IIEasy
- 456Next Closest TimeMedium
- 463Count Binary SubstringsEasy
- 479Remove CommentsMedium
- 483Minimum Window SubsequenceHard
- 490Prefix and Suffix SearchHard
- 492Open the LockMedium
- 498Jewels and StonesEasy
- 499Basic Calculator IIIHard
- 502Letter Case PermutationMedium
- 506Custom Sort StringMedium
- 507Number of Matching SubsequencesMedium
- 511Most Common WordEasy
- 512Goat LatinEasy
- 515Find And Replace in StringMedium
- 518Backspace String CompareEasy
- 521Shifting LettersMedium
- 526Score of ParenthesesMedium
- 528Buddy StringsEasy
- 553Minimum Add to Make Parentheses ValidMedium
- 554Unique Email AddressesEasy
- 559Reorder Data in Log FilesMedium
- 568Verifying an Alien DictionaryEasy
- 587Find Common CharactersEasy
- 594Remove All Adjacent Duplicates In StringEasy
- 595Longest String ChainMedium
- 596Greatest Common Divisor of StringsEasy
- 601Longest Common SubsequenceMedium
- 605Maximum Number of BalloonsEasy
- 608Remove All Adjacent Duplicates in String IIMedium
- 609Valid Palindrome IIIHard
- 611Minimum Remove to Make Valid ParenthesesMedium
- 612Search Suggestions SystemMedium
- 626Maximum Number of Vowels in a Substring of Given LengthMedium
- 637Determine if Two Strings Are CloseMedium
- 645Merge Strings AlternatelyEasy
- 660Longest Palindrome by Concatenating Two Letter WordsMedium
- 667Removing Stars From a StringMedium
- 668Optimal Partition of StringMedium