Problem set
Hashing questions
114 matching · 33 easy · 68 medium · 13 hard
- 01Two SumEasy
- 03Longest Substring Without Repeating CharactersMedium
- 12Integer to RomanMedium
- 13Roman to IntegerEasy
- 17Letter Combinations of a Phone NumberMedium
- 30Substring with Concatenation of All WordsHard
- 36Valid SudokuMedium
- 41First Missing PositiveHard
- 49Group AnagramsMedium
- 73Set Matrix ZeroesMedium
- 76Minimum Window SubstringHard
- 105Construct Binary Tree from Preorder and Inorder TraversalMedium
- 106Construct Binary Tree from Inorder and Postorder TraversalMedium
- 128Longest Consecutive SequenceMedium
- 133Clone GraphMedium
- 138Copy List with Random PointerMedium
- 146LRU CacheMedium
- 149Max Points on a LineHard
- 157Longest Substring with At Most Two Distinct CharactersMedium
- 164Fraction to Recurring DecimalMedium
- 167Majority ElementEasy
- 173Repeated DNA SequencesMedium
- 182Happy NumberEasy
- 185Isomorphic StringsEasy
- 194Shortest PalindromeHard
- 197Contains DuplicateEasy
- 199Contains Duplicate IIEasy
- 209Majority Element IIMedium
- 222Valid AnagramEasy
- 224Shortest Word Distance IIMedium
- 225Strobogrammatic NumberEasy
- 226Group Shifted StringsMedium
- 237Palindrome PermutationEasy
- 256Word PatternEasy
- 261Bulls and CowsMedium
- 277Maximum Size Subarray Sum Equals kMedium
- 283Palindrome PairsHard
- 287Longest Substring with At Most K Distinct CharactersMedium
- 294Top K Frequent ElementsMedium
- 296Intersection of Two ArraysEasy
- 297Intersection of Two Arrays IIEasy
- 299Design TwitterMedium
- 300Logger Rate LimiterEasy
- 316Insert Delete GetRandom O(1)Medium
- 317Insert Delete GetRandom O(1) - Duplicates allowedHard
- 319Ransom NoteEasy
- 322First Unique Character in a StringEasy
- 324Find the DifferenceEasy
- 337Longest PalindromeEasy
- 347Longest Repeating Character ReplacementMedium
- 351All O`one Data StructureHard
- 356Find All Anagrams in a StringMedium
- 358Find All Duplicates in an ArrayMedium
- 361Find All Numbers Disappeared in an ArrayEasy
- 364Sort Characters By FrequencyMedium
- 3664Sum IIMedium
- 370LFU CacheHard
- 386Next Greater Element IEasy
- 396Continuous Subarray SumMedium
- 397Contiguous ArrayMedium
- 402K-diff Pairs in an ArrayMedium
- 403Encode and Decode TinyURLMedium
- 413Brick WallMedium
- 416Subarray Sum Equals KMedium
- 419Permutation in StringMedium
- 423Design In-Memory File SystemHard
- 430Task SchedulerMedium
- 439Set MismatchEasy
- 441Replace WordsMedium
- 444Find Duplicate SubtreesMedium
- 445Two Sum IV - Input is a BSTEasy
- 460Top K Frequent WordsMedium
- 461Number of Distinct IslandsMedium
- 468Design HashSetEasy
- 469Design HashMapEasy
- 478Accounts MergeMedium
- 495Partition LabelsMedium
- 497Reorganize StringMedium
- 498Jewels and StonesEasy
- 506Custom Sort StringMedium
- 507Number of Matching SubsequencesMedium
- 510Bus RoutesHard
- 511Most Common WordEasy
- 520Hand of StraightsMedium
- 528Buddy StringsEasy
- 543Maximum Frequency StackHard
- 547Fruit Into BasketsMedium
- 554Unique Email AddressesEasy
- 561Minimum Area RectangleMedium
- 568Verifying an Alien DictionaryEasy
- 569Prison Cells After N DaysMedium
- 573Subarray Sums Divisible by KMedium
- 577Time Based Key-Value StoreMedium
- 580Vertical Order Traversal of a Binary TreeHard
- 585Find the Town JudgeEasy
- 587Find Common CharactersEasy
- 590Pairs of Songs With Total Durations Divisible by 60Medium
- 595Longest String ChainMedium
- 603Analyze User Website Visit PatternMedium
- 605Maximum Number of BalloonsEasy
- 620Design Underground SystemMedium
- 633Dot Product of Two Sparse VectorsMedium
- 636Lowest Common Ancestor of a Binary Tree IIIMedium
- 637Determine if Two Strings Are CloseMedium
- 640Maximum Erasure ValueMedium
- 654Detect SquaresMedium
- 655Stock Price FluctuationMedium
- 658Find All Possible Recipes from Given SuppliesMedium
- 660Longest Palindrome by Concatenating Two Letter WordsMedium
- 661Find the Difference of Two ArraysEasy
- 662Find Players With Zero or One LossesMedium
- 664Smallest Number in Infinite SetMedium
- 666Equal Row and Column PairsMedium
- 668Optimal Partition of StringMedium