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Hash Table Interview Questions

87 Hash Table problems asked across FAANG and top tech companies. Approach hints, optimal solutions, and related problems.

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✓ 0ProblemDifficultyCompaniesBreakdown / SolutionLeetCode
Two SumEasy9 companiesView breakdown →
Longest Substring Without Repeating CharactersMedium11 companiesView breakdown →
Group AnagramsMedium8 companiesView breakdown →
Top K Frequent ElementsMedium7 companiesView breakdown →
Longest Consecutive SequenceMedium6 companiesView breakdown →
Subarray Sum Equals KMedium5 companiesView breakdown →
LRU CacheMedium9 companiesView breakdown →
Word BreakMedium9 companiesView breakdown →
Find All Anagrams in a StringMedium6 companiesView breakdown →
Clone GraphMedium5 companiesView breakdown →
Task SchedulerMedium6 companiesView breakdown →
LFU CacheHard4 companiesView breakdown →
Snapshot ArrayMedium3 companiesView breakdown →
Permutation in StringMedium3 companiesView breakdown →
Time Based Key-Value StoreMedium5 companiesView breakdown →
Minimum Window SubstringHard4 companiesView breakdown →
Roman to IntegerEasy4 companiesView breakdown →
Letter Combinations of a Phone NumberMedium4 companiesView breakdown →
Integer to RomanMedium2 companiesView breakdown →
Insert Delete GetRandom O(1)Medium2 companiesView breakdown →
Accounts MergeMedium2 companiesView breakdown →
Design Memory AllocatorMedium3 companiesView breakdown →
Fruit Into BasketsMedium3 companiesView breakdown →
Majority ElementEasy3 companiesView breakdown →
First Missing PositiveHard3 companiesView breakdown →
Copy List with Random PointerMedium3 companiesView breakdown →
Design SQLMedium1 companiesView breakdown →
Find the Largest Almost Missing IntegerEasy2 companiesView breakdown →
First Unique NumberMedium1 companiesView breakdown →
Longest Repeating Character ReplacementMedium1 companiesView breakdown →
Design Authentication ManagerMedium2 companiesView breakdown →
Meeting Rooms IIIHard2 companiesView breakdown →
Word LadderHard2 companiesView breakdown →
Contains Duplicate IIEasy2 companiesView breakdown →
Design Logger Rate LimiterEasy2 companiesView breakdown →
Contains DuplicateEasy2 companiesView breakdown →
Stock Price FluctuationMedium1 companiesView breakdown →
Design SpreadsheetMedium2 companiesView breakdown →
Design Excel Sum FormulaHard2 companiesView breakdown →
Find the Length of the Longest Common PrefixMedium1 companiesView breakdown →
Count Vowel Substrings of a StringEasy1 companiesView breakdown →
All O'one Data StructureHard1 companiesView breakdown →
Alphabet Board PathMedium1 companiesView breakdown →
Amount of Time for Binary Tree to Be InfectedMedium1 companiesView breakdown →
Binary Tree Vertical Order TraversalMedium1 companiesView breakdown →
Bus RoutesHard1 companiesView breakdown →
Cinema Seat AllocationMedium1 companiesView breakdown →
Count Paths That Can Form a Palindrome in a TreeHard1 companiesView breakdown →
Delete and EarnMedium1 companiesView breakdown →
Design a Food Rating SystemMedium1 companiesView breakdown →
Design In-Memory File SystemHard1 companiesView breakdown →
Design Ride Sharing SystemMedium1 companiesView breakdown →
Design Snake GameMedium1 companiesView breakdown →
Design Task ManagerMedium1 companiesView breakdown →
Design Tic-Tac-ToeMedium1 companiesView breakdown →
Design Underground SystemMedium1 companiesView breakdown →
Linked List CycleEASY1 companiesView breakdown →
Longest String ChainMEDIUM1 companiesView breakdown →
High-Access EmployeesMEDIUM1 companiesView breakdown →
Find Duplicate File in SystemMEDIUM1 companiesView breakdown →
Maximum Sum of Distinct Subarrays With Length KMEDIUM1 companiesView breakdown →
Maximum Length Substring With Two OccurrencesEASY1 companiesView breakdown →
Rank Teams by VotesMEDIUM1 companiesView breakdown →
Rearranging FruitsHARD1 companiesView breakdown →
Reorganize StringMEDIUM1 companiesView breakdown →
Maximum Palindromes After OperationsMEDIUM1 companiesView breakdown →
Maximum Score with Co-Prime ElementHARD1 companiesView breakdown →
Number of Flowers in Full BloomHARD1 companiesView breakdown →
Number of Islands IIHARD1 companiesView breakdown →
Number of Wonderful SubstringsMEDIUM1 companiesView breakdown →
Set Matrix ZeroesMEDIUM1 companiesView breakdown →
Valid SudokuMedium1 companiesView breakdown →
Set MismatchEASY1 companiesView breakdown →
Smallest Missing Multiple of KEASY1 companiesView breakdown →
Top K Frequent WordsMEDIUM1 companiesView breakdown →
Pairs of Songs With Total Durations Divisible by 60MEDIUM1 companiesView breakdown →
Sentence Similarity IIMEDIUM1 companiesView breakdown →
Lowest Common Ancestor of a Binary Tree IIIMEDIUM1 companiesView breakdown →
Lowest Common Ancestor of a Binary Tree IVMEDIUM1 companiesView breakdown →
Sum of Matrix After QueriesMedium1 companiesView breakdown →
Synonymous SentencesMEDIUM1 companiesView breakdown →
Using a Robot to Print the Lexicographically Smallest StringMEDIUM1 companiesView breakdown →
Vertical Order Traversal of a Binary TreeHARD1 companiesView breakdown →
Word Break IIHard1 companiesView breakdown →
Valid AnagramEasy4 companiesView breakdown →
Missing NumberEasy4 companiesView breakdown →
Happy NumberEasy4 companiesView breakdown →

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