← Back to Google

Hash Table

433 questions

1Longest Substring Without Repeating CharactersMedium
Hash TableStringSliding Window
Solve →
2Roman to IntegerEasy
Hash TableMathString
Solve →
3Logger Rate LimiterEasy
Hash TableDesignData Stream
Solve →
4LRU CacheMedium
Hash TableLinked ListDesign
Solve →
5Valid AnagramEasy
Hash TableStringSorting
Solve →
6Count the Number of Special Characters IIMedium
Hash TableString
Solve →
7Longest Repeating Character ReplacementMedium
Hash TableStringSliding Window
Solve →
8Implement Trie (Prefix Tree)Medium
Hash TableStringDesign
Solve →
9Letter Combinations of a Phone NumberMedium
Hash TableStringBacktracking
Solve →
10Minimum Window SubstringHard
Hash TableStringSliding Window
Solve →
11First Unique Character in a StringEasy
Hash TableStringQueue
Solve →
12Permutation in StringMedium
Hash TableTwo PointersString
Solve →
13Ransom NoteEasy
Hash TableStringCounting
Solve →
14Word Ladder IIHard
Hash TableStringBacktracking
Solve →
15Isomorphic StringsEasy
Hash TableString
Solve →
16Maximum Number of BalloonsEasy
Hash TableStringCounting
Solve →
17Longest Substring Without Repeating CharactersMedium
Hash TableStringSliding Window
Solve →
18Roman to IntegerEasy
Hash TableMathString
Solve →
19LRU CacheMedium
Hash TableLinked ListDesign
Solve →
20Valid AnagramEasy
Hash TableStringSorting
Solve →
21Longest Repeating Character ReplacementMedium
Hash TableStringSliding Window
Solve →
22Letter Combinations of a Phone NumberMedium
Hash TableStringBacktracking
Solve →
23Logger Rate LimiterEasy
Hash TableDesignData Stream
Solve →
24Happy NumberEasy
Hash TableMathTwo Pointers
Solve →
25Integer to RomanMedium
Hash TableMathString
Solve →
26Word Ladder IIHard
Hash TableStringBacktracking
Solve →
27Isomorphic StringsEasy
Hash TableString
Solve →
28First Unique Character in a StringEasy
Hash TableStringQueue
Solve →
29Count the Number of Special Characters IIMedium
Hash TableString
Solve →
30Minimum Window SubstringHard
Hash TableStringSliding Window
Solve →
31Word LadderHard
Hash TableStringBreadth-First Search
Solve →
32Clone GraphMedium
Hash TableDepth-First SearchBreadth-First Search
Solve →
33Implement Trie (Prefix Tree)Medium
Hash TableStringDesign
Solve →
34Copy List with Random PointerMedium
Hash TableLinked List
Solve →
35Ransom NoteEasy
Hash TableStringCounting
Solve →
36Reorganize StringMedium
Hash TableStringGreedy
Solve →
37Substring with Concatenation of All WordsHard
Hash TableStringSliding Window
Solve →
38Check if Strings Can be Made Equal With Operations IIMedium
Hash TableStringSorting
Solve →
39Time Based Key-Value StoreMedium
Hash TableStringBinary Search
Solve →
40Linked List Cycle IIMedium
Hash TableLinked ListTwo Pointers
Solve →
41Design TwitterMedium
Hash TableLinked ListDesign
Solve →
42Permutation in StringMedium
Hash TableTwo PointersString
Solve →
43Minimum Genetic MutationMedium
Hash TableStringBreadth-First Search
Solve →
44Two Sum IV - Input is a BSTEasy
Hash TableTwo PointersTree
Solve →
45Linked List CycleEasy
Hash TableLinked ListTwo Pointers
Solve →
46Maximum Number of BalloonsEasy
Hash TableStringCounting
Solve →
47Longest Substring Without Repeating CharactersMedium
Hash TableStringSliding Window
Solve →
48Roman to IntegerEasy
Hash TableMathString
Solve →
49Valid AnagramEasy
Hash TableStringSorting
Solve →
50LRU CacheMedium
Hash TableLinked ListDesign
Solve →
51Longest Repeating Character ReplacementMedium
Hash TableStringSliding Window
Solve →
52Letter Combinations of a Phone NumberMedium
Hash TableStringBacktracking
Solve →
53Logger Rate LimiterEasy
Hash TableDesignData Stream
Solve →
54Isomorphic StringsEasy
Hash TableString
Solve →
55Happy NumberEasy
Hash TableMathTwo Pointers
Solve →
56Ransom NoteEasy
Hash TableStringCounting
Solve →
57First Unique Character in a StringEasy
Hash TableStringQueue
Solve →
58Linked List CycleEasy
Hash TableLinked ListTwo Pointers
Solve →
59Word LadderHard
Hash TableStringBreadth-First Search
Solve →
60Intersection of Two Linked ListsEasy
Hash TableLinked ListTwo Pointers
Solve →
61Minimum Window SubstringHard
Hash TableStringSliding Window
Solve →
62Integer to RomanMedium
Hash TableMathString
Solve →
63Reorganize StringMedium
Hash TableStringGreedy
Solve →
64Word Ladder IIHard
Hash TableStringBacktracking
Solve →
65Permutation in StringMedium
Hash TableTwo PointersString
Solve →
66Clone GraphMedium
Hash TableDepth-First SearchBreadth-First Search
Solve →
67Substring with Concatenation of All WordsHard
Hash TableStringSliding Window
Solve →
68Time Based Key-Value StoreMedium
Hash TableStringBinary Search
Solve →
69Check If a String Contains All Binary Codes of Size KMedium
Hash TableStringBit Manipulation
Solve →
70Implement Trie (Prefix Tree)Medium
Hash TableStringDesign
Solve →
71Count the Number of Special Characters IIMedium
Hash TableString
Solve →
72Copy List with Random PointerMedium
Hash TableLinked List
Solve →
73Linked List Cycle IIMedium
Hash TableLinked ListTwo Pointers
Solve →
74Find All Anagrams in a StringMedium
Hash TableStringSliding Window
Solve →
75Number of Substrings Containing All Three CharactersMedium
Hash TableStringSliding Window
Solve →
76LFU CacheHard
Hash TableLinked ListDesign
Solve →
77Two Sum IV - Input is a BSTEasy
Hash TableTwo PointersTree
Solve →
78Most Stones Removed with Same Row or ColumnMedium
Hash TableDepth-First SearchUnion-Find
Solve →
79Pyramid Transition MatrixMedium
Hash TableStringBacktracking
Solve →
80Design Auction SystemMedium
Hash TableDesignHeap (Priority Queue)
Solve →
81Longest PalindromeEasy
Hash TableStringGreedy
Solve →
82Longest Balanced Substring IIMedium
Hash TableStringPrefix Sum
Solve →
83Sum of Beauty of All SubstringsMedium
Hash TableStringCounting
Solve →
84Check if Strings Can be Made Equal With Operations IIMedium
Hash TableStringSorting
Solve →
85Jewels and StonesEasy
Hash TableString
Solve →
86Find the DifferenceEasy
Hash TableStringBit Manipulation
Solve →
87Check if the Sentence Is PangramEasy
Hash TableString
Solve →
88Sort Characters By FrequencyMedium
Hash TableStringSorting
Solve →
89Fraction to Recurring DecimalMedium
Hash TableMathString
Solve →
90Smallest Integer Divisible by KMedium
Hash TableMath
Solve →
91Remove Letter To Equalize FrequencyEasy
Hash TableStringCounting
Solve →
92Count Vowel Substrings of a StringEasy
Hash TableString
Solve →
93Smallest Subtree with all the Deepest NodesMedium
Hash TableTreeDepth-First Search
Solve →
94Count Residue PrefixesEasy
Hash TableString
Solve →
95Find Most Frequent Vowel and ConsonantEasy
Hash TableStringCounting
Solve →
96Determine if Two Strings Are CloseMedium
Hash TableStringSorting
Solve →
97Longest Balanced Substring IMedium
Hash TableStringCounting
Solve →
98First Letter to Appear TwiceEasy
Hash TableStringBit Manipulation
Solve →
99Longest Substring with At Least K Repeating CharactersMedium
Hash TableStringDivide and Conquer
Solve →
100Number of Wonderful SubstringsMedium
Hash TableStringBit Manipulation
Solve →
101Word PatternEasy
Hash TableString
Solve →
102Repeated DNA SequencesMedium
Hash TableStringBit Manipulation
Solve →
103Design TwitterMedium
Hash TableLinked ListDesign
Solve →
104Minimum Genetic MutationMedium
Hash TableStringBreadth-First Search
Solve →
105Maximum Number of BalloonsEasy
Hash TableStringCounting
Solve →
106All Nodes Distance K in Binary TreeMedium
Hash TableTreeDepth-First Search
Solve →
107Longest Substring Without Repeating CharactersMedium
Hash TableStringSliding Window
Solve →
108Roman to IntegerEasy
Hash TableMathString
Solve →
109Letter Combinations of a Phone NumberMedium
Hash TableStringBacktracking
Solve →
110LRU CacheMedium
Hash TableLinked ListDesign
Solve →
111Happy NumberEasy
Hash TableMathTwo Pointers
Solve →
112Valid AnagramEasy
Hash TableStringSorting
Solve →
113Logger Rate LimiterEasy
Hash TableDesignData Stream
Solve →
114Longest Repeating Character ReplacementMedium
Hash TableStringSliding Window
Solve →
115Linked List CycleEasy
Hash TableLinked ListTwo Pointers
Solve →
116Isomorphic StringsEasy
Hash TableString
Solve →
117Permutation in StringMedium
Hash TableTwo PointersString
Solve →
118Integer to RomanMedium
Hash TableMathString
Solve →
119Minimum Window SubstringHard
Hash TableStringSliding Window
Solve →
120Word LadderHard
Hash TableStringBreadth-First Search
Solve →
121Find the DifferenceEasy
Hash TableStringBit Manipulation
Solve →
122Copy List with Random PointerMedium
Hash TableLinked List
Solve →
123Intersection of Two Linked ListsEasy
Hash TableLinked ListTwo Pointers
Solve →
124Vertical Order Traversal of a Binary TreeHard
Hash TableTreeDepth-First Search
Solve →
125Reorganize StringMedium
Hash TableStringGreedy
Solve →
126First Unique Character in a StringEasy
Hash TableStringQueue
Solve →
127Linked List Cycle IIMedium
Hash TableLinked ListTwo Pointers
Solve →
128Clone GraphMedium
Hash TableDepth-First SearchBreadth-First Search
Solve →
129Ransom NoteEasy
Hash TableStringCounting
Solve →
130Unique Length-3 Palindromic SubsequencesMedium
Hash TableStringBit Manipulation
Solve →
131Substring with Concatenation of All WordsHard
Hash TableStringSliding Window
Solve →
132LFU CacheHard
Hash TableLinked ListDesign
Solve →
133Find All Anagrams in a StringMedium
Hash TableStringSliding Window
Solve →
134Jewels and StonesEasy
Hash TableString
Solve →
135Implement Trie (Prefix Tree)Medium
Hash TableStringDesign
Solve →
136Find Longest Special Substring That Occurs Thrice IMedium
Hash TableStringBinary Search
Solve →
137All Nodes Distance K in Binary TreeMedium
Hash TableTreeDepth-First Search
Solve →
138Sort Characters By FrequencyMedium
Hash TableStringSorting
Solve →
139Design a Number Container SystemMedium
Hash TableDesignHeap (Priority Queue)
Solve →
140Find Duplicate SubtreesMedium
Hash TableTreeDepth-First Search
Solve →
141Fraction to Recurring DecimalMedium
Hash TableMathString
Solve →
142All O`one Data StructureHard
Hash TableLinked ListDesign
Solve →
143Two Sum IV - Input is a BSTEasy
Hash TableTwo PointersTree
Solve →
144Binary Tree Vertical Order TraversalMedium
Hash TableTreeDepth-First Search
Solve →
145Time Based Key-Value StoreMedium
Hash TableStringBinary Search
Solve →
146Word Ladder IIHard
Hash TableStringBacktracking
Solve →
147Longest PalindromeEasy
Hash TableStringGreedy
Solve →
148Number of Substrings Containing All Three CharactersMedium
Hash TableStringSliding Window
Solve →
149Design Task ManagerMedium
Hash TableDesignHeap (Priority Queue)
Solve →
150Word PatternEasy
Hash TableString
Solve →
151Reordered Power of 2Medium
Hash TableMathSorting
Solve →
152Partition StringMedium
Hash TableStringTrie
Solve →
153Repeated DNA SequencesMedium
Hash TableStringBit Manipulation
Solve →
154Smallest Integer Divisible by KMedium
Hash TableMath
Solve →
155Design TwitterMedium
Hash TableLinked ListDesign
Solve →
156Longest Substring with At Least K Repeating CharactersMedium
Hash TableStringDivide and Conquer
Solve →
157Most Stones Removed with Same Row or ColumnMedium
Hash TableDepth-First SearchUnion-Find
Solve →
158Sum of Beauty of All SubstringsMedium
Hash TableStringCounting
Solve →
159Stock Price FluctuationMedium
Hash TableDesignHeap (Priority Queue)
Solve →
160Buddy StringsEasy
Hash TableString
Solve →
161First Letter to Appear TwiceEasy
Hash TableStringBit Manipulation
Solve →
162Lowest Common Ancestor of a Binary Tree IIIMedium
Hash TableTwo PointersTree
Solve →
163Next Greater Numerically Balanced NumberMedium
Hash TableMathBacktracking
Solve →
164Ugly Number IIMedium
Hash TableMathDynamic Programming
Solve →
165Determine if Two Strings Are CloseMedium
Hash TableStringSorting
Solve →
166Check if the Sentence Is PangramEasy
Hash TableString
Solve →
167Partition LabelsMedium
Hash TableTwo PointersString
Solve →
168Minimum Genetic MutationMedium
Hash TableStringBreadth-First Search
Solve →
169Next Closest TimeMedium
Hash TableStringBacktracking
Solve →
170Number of Good Ways to Split a StringMedium
Hash TableStringDynamic Programming
Solve →
171Bulls and CowsMedium
Hash TableStringCounting
Solve →
172Split a String Into the Max Number of Unique SubstringsMedium
Hash TableStringBacktracking
Solve →
173Construct K Palindrome StringsMedium
Hash TableStringGreedy
Solve →
174Cousins in Binary Tree IIMedium
Hash TableTreeDepth-First Search
Solve →
175Find the Count of Good IntegersHard
Hash TableMathCombinatorics
Solve →
176Lowest Common Ancestor of Deepest LeavesMedium
Hash TableTreeDepth-First Search
Solve →
177Count Largest GroupEasy
Hash TableMathCounting
Solve →
178Take K of Each Character From Left and RightMedium
Hash TableStringSliding Window
Solve →
179Construct String With Repeat LimitMedium
Hash TableStringGreedy
Solve →
180Longest Subsequence Repeated k TimesHard
Hash TableTwo PointersString
Solve →
181Minimum Number of Steps to Make Two Strings AnagramMedium
Hash TableStringCounting
Solve →
182Number of AtomsHard
Hash TableStringStack
Solve →
183Find the Longest Substring Containing Vowels in Even CountsMedium
Hash TableStringBit Manipulation
Solve →
184Encode and Decode TinyURLMedium
Hash TableStringDesign
Solve →
185Implement Magic DictionaryMedium
Hash TableStringDepth-First Search
Solve →
186Pyramid Transition MatrixMedium
Hash TableStringBacktracking
Solve →
187Letter Tile PossibilitiesMedium
Hash TableStringBacktracking
Solve →
188Total Characters in String After Transformations IIHard
Hash TableMathString
Solve →
189Smallest Number in Infinite SetMedium
Hash TableDesignHeap (Priority Queue)
Solve →
190Reconstruct Original Digits from EnglishMedium
Hash TableMathString
Solve →
191Lexicographically Minimum String After Removing StarsMedium
Hash TableStringStack
Solve →
192Maximum Number of Words You Can TypeEasy
Hash TableString
Solve →
193Path CrossingEasy
Hash TableString
Solve →
194Largest Color Value in a Directed GraphHard
Hash TableStringDynamic Programming
Solve →
195Design In-Memory File SystemHard
Hash TableStringDesign
Solve →
196Design File SystemMedium
Hash TableStringDesign
Solve →
197Rearrange String k Distance ApartHard
Hash TableStringGreedy
Solve →
198Longest Substring with At Most Two Distinct CharactersMedium
Hash TableStringSliding Window
Solve →
199Check if Number Has Equal Digit Count and Digit ValueEasy
Hash TableStringCounting
Solve →
200K-Similar StringsHard
Hash TableStringBreadth-First Search
Solve →
201Single-Row KeyboardEasy
Hash TableString
Solve →
202Basic Calculator IVHard
Hash TableMathString
Solve →
203Uncommon Words from Two SentencesEasy
Hash TableStringCounting
Solve →
204Tweet Counts Per FrequencyMedium
Hash TableStringBinary Search
Solve →
205Check if One String Swap Can Make Strings EqualEasy
Hash TableStringCounting
Solve →
206Custom Sort StringMedium
Hash TableStringSorting
Solve →
207Count Vowel Substrings of a StringEasy
Hash TableString
Solve →
208Longest Substring with At Most K Distinct CharactersMedium
Hash TableStringSliding Window
Solve →
209Alphabet Board PathMedium
Hash TableString
Solve →
210Count K-Subsequences of a String With Maximum BeautyHard
Hash TableMathString
Solve →
211Find Longest Special Substring That Occurs Thrice IIMedium
Hash TableStringBinary Search
Solve →
212Amount of Time for Binary Tree to Be InfectedMedium
Hash TableTreeDepth-First Search
Solve →
213Longest Nice SubstringEasy
Hash TableStringDivide and Conquer
Solve →
214Strobogrammatic NumberEasy
Hash TableTwo PointersString
Solve →
215Longest Uploaded PrefixMedium
Hash TableBinary SearchUnion-Find
Solve →
216Make Number of Distinct Characters EqualMedium
Hash TableStringCounting
Solve →
217Binary String With Substrings Representing 1 To NMedium
Hash TableStringBit Manipulation
Solve →
218Brace Expansion IIHard
Hash TableStringBacktracking
Solve →
219Minimum Number of Operations to Make Word K-PeriodicMedium
Hash TableStringCounting
Solve →
220Find Root of N-Ary TreeMedium
Hash TableBit ManipulationTree
Solve →
221Throne InheritanceMedium
Hash TableTreeDepth-First Search
Solve →
222Count the Number of Special Characters IEasy
Hash TableString
Solve →
223Remove Letter To Equalize FrequencyEasy
Hash TableStringCounting
Solve →
224Swap For Longest Repeated Character SubstringMedium
Hash TableStringSliding Window
Solve →
225Total Appeal of A StringHard
Hash TableStringDynamic Programming
Solve →
226Total Characters in String After Transformations IMedium
Hash TableMathString
Solve →
227Find Most Frequent Vowel and ConsonantEasy
Hash TableStringCounting
Solve →
228Parse Lisp ExpressionHard
Hash TableStringStack
Solve →
229Design Underground SystemMedium
Hash TableStringDesign
Solve →
230Maximum Difference Between Even and Odd Frequency IEasy
Hash TableStringCounting
Solve →
231Decode the MessageEasy
Hash TableString
Solve →
232Optimal Partition of StringMedium
Hash TableStringGreedy
Solve →
233Remove Zero Sum Consecutive Nodes from Linked ListMedium
Hash TableLinked List
Solve →
234Rings and RodsEasy
Hash TableString
Solve →
235HTML Entity ParserMedium
Hash TableString
Solve →
236Palindrome PermutationEasy
Hash TableStringBit Manipulation
Solve →
237Design Video Sharing PlatformHard
Hash TableDesignHeap (Priority Queue)
Solve →
238Random Flip MatrixMedium
Hash TableMathReservoir Sampling
Solve →
239String Transforms Into Another StringHard
Hash TableStringGraph Theory
Solve →
240Find Elements in a Contaminated Binary TreeMedium
Hash TableTreeDepth-First Search
Solve →
241Check If a String Contains All Binary Codes of Size KMedium
Hash TableStringBit Manipulation
Solve →
242Check If Two Expression Trees are EquivalentMedium
Hash TableTreeDepth-First Search
Solve →
243Correct a Binary TreeMedium
Hash TableTreeDepth-First Search
Solve →
244Change Minimum Characters to Satisfy One of Three ConditionsMedium
Hash TableStringCounting
Solve →
245Count Pairs of Equal Substrings With Minimum DifferenceMedium
Hash TableStringGreedy
Solve →
246Number of Wonderful SubstringsMedium
Hash TableStringBit Manipulation
Solve →
247Check if All Characters Have Equal Number of OccurrencesEasy
Hash TableStringCounting
Solve →
248Count Substrings With K-Frequency Characters IMedium
Hash TableStringSliding Window
Solve →
249Minimum Operations to Make Character Frequencies EqualHard
Hash TableStringDynamic Programming
Solve →
250Map Sum PairsMedium
Hash TableStringDesign
Solve →
251Minimum Deletions to Make String K-SpecialMedium
Hash TableStringGreedy
Solve →
252Data Stream as Disjoint IntervalsHard
Hash TableBinary SearchUnion-Find
Solve →
253Maximum Frequency StackHard
Hash TableStackDesign
Solve →
254Smallest Subtree with all the Deepest NodesMedium
Hash TableTreeDepth-First Search
Solve →
255Increasing Decreasing StringEasy
Hash TableStringCounting
Solve →
256Minimum Deletions to Make Character Frequencies UniqueMedium
Hash TableStringGreedy
Solve →
257Find Mirror Score of a StringMedium
Hash TableStringStack
Solve →
258Minimize String LengthEasy
Hash TableString
Solve →
259Lexicographically Smallest Permutation Greater Than TargetMedium
Hash TableStringGreedy
Solve →
260Longest Balanced Substring IIMedium
Hash TableStringPrefix Sum
Solve →
261Second Largest Digit in a StringEasy
Hash TableString
Solve →
262Dinner Plate StacksHard
Hash TableStackDesign
Solve →
263Count Paths That Can Form a Palindrome in a TreeHard
Hash TableBit ManipulationTree
Solve →
264Design A LeaderboardMedium
Hash TableDesignSorting
Solve →
265Longest Substring Without Repeating CharactersMedium
Hash TableStringSliding Window
Solve →
266Roman to IntegerEasy
Hash TableMathString
Solve →
267LRU CacheMedium
Hash TableLinked ListDesign
Solve →
268Letter Combinations of a Phone NumberMedium
Hash TableStringBacktracking
Solve →
269Valid AnagramEasy
Hash TableStringSorting
Solve →
270Logger Rate LimiterEasy
Hash TableDesignData Stream
Solve →
271Happy NumberEasy
Hash TableMathTwo Pointers
Solve →
272Longest Repeating Character ReplacementMedium
Hash TableStringSliding Window
Solve →
273Linked List CycleEasy
Hash TableLinked ListTwo Pointers
Solve →
274Isomorphic StringsEasy
Hash TableString
Solve →
275Integer to RomanMedium
Hash TableMathString
Solve →
276Minimum Window SubstringHard
Hash TableStringSliding Window
Solve →
277Permutation in StringMedium
Hash TableTwo PointersString
Solve →
278First Unique Character in a StringEasy
Hash TableStringQueue
Solve →
279Find the DifferenceEasy
Hash TableStringBit Manipulation
Solve →
280Word LadderHard
Hash TableStringBreadth-First Search
Solve →
281Intersection of Two Linked ListsEasy
Hash TableLinked ListTwo Pointers
Solve →
282Clone GraphMedium
Hash TableDepth-First SearchBreadth-First Search
Solve →
283Copy List with Random PointerMedium
Hash TableLinked List
Solve →
284Ransom NoteEasy
Hash TableStringCounting
Solve →
285Reorganize StringMedium
Hash TableStringGreedy
Solve →
286LFU CacheHard
Hash TableLinked ListDesign
Solve →
287Implement Trie (Prefix Tree)Medium
Hash TableStringDesign
Solve →
288Linked List Cycle IIMedium
Hash TableLinked ListTwo Pointers
Solve →
289Substring with Concatenation of All WordsHard
Hash TableStringSliding Window
Solve →
290Vertical Order Traversal of a Binary TreeHard
Hash TableTreeDepth-First Search
Solve →
291Find Longest Special Substring That Occurs Thrice IMedium
Hash TableStringBinary Search
Solve →
292Sort Characters By FrequencyMedium
Hash TableStringSorting
Solve →
293Fraction to Recurring DecimalMedium
Hash TableMathString
Solve →
294Unique Length-3 Palindromic SubsequencesMedium
Hash TableStringBit Manipulation
Solve →
295Design a Number Container SystemMedium
Hash TableDesignHeap (Priority Queue)
Solve →
296Find All Anagrams in a StringMedium
Hash TableStringSliding Window
Solve →
297Longest PalindromeEasy
Hash TableStringGreedy
Solve →
298Find Duplicate SubtreesMedium
Hash TableTreeDepth-First Search
Solve →
299Binary Tree Vertical Order TraversalMedium
Hash TableTreeDepth-First Search
Solve →
300Jewels and StonesEasy
Hash TableString
Solve →
301Smallest Integer Divisible by KMedium
Hash TableMath
Solve →
302Sum of Beauty of All SubstringsMedium
Hash TableStringCounting
Solve →
303All Nodes Distance K in Binary TreeMedium
Hash TableTreeDepth-First Search
Solve →
304Word Ladder IIHard
Hash TableStringBacktracking
Solve →
305First Letter to Appear TwiceEasy
Hash TableStringBit Manipulation
Solve →
306Two Sum IV - Input is a BSTEasy
Hash TableTwo PointersTree
Solve →
307Time Based Key-Value StoreMedium
Hash TableStringBinary Search
Solve →
308Stock Price FluctuationMedium
Hash TableDesignHeap (Priority Queue)
Solve →
309Pyramid Transition MatrixMedium
Hash TableStringBacktracking
Solve →
310Number of Substrings Containing All Three CharactersMedium
Hash TableStringSliding Window
Solve →
311Buddy StringsEasy
Hash TableString
Solve →
312Check If a String Contains All Binary Codes of Size KMedium
Hash TableStringBit Manipulation
Solve →
313Bulls and CowsMedium
Hash TableStringCounting
Solve →
314All O`one Data StructureHard
Hash TableLinked ListDesign
Solve →
315Implement Magic DictionaryMedium
Hash TableStringDepth-First Search
Solve →
316Number of Good Ways to Split a StringMedium
Hash TableStringDynamic Programming
Solve →
317Split a String Into the Max Number of Unique SubstringsMedium
Hash TableStringBacktracking
Solve →
318Next Closest TimeMedium
Hash TableStringBacktracking
Solve →
319Number of AtomsHard
Hash TableStringStack
Solve →
320Word PatternEasy
Hash TableString
Solve →
321Rearrange String k Distance ApartHard
Hash TableStringGreedy
Solve →
322Encode and Decode TinyURLMedium
Hash TableStringDesign
Solve →
323Most Stones Removed with Same Row or ColumnMedium
Hash TableDepth-First SearchUnion-Find
Solve →
324Letter Tile PossibilitiesMedium
Hash TableStringBacktracking
Solve →
325Longest Substring with At Most Two Distinct CharactersMedium
Hash TableStringSliding Window
Solve →
326K-Similar StringsHard
Hash TableStringBreadth-First Search
Solve →
327Binary String With Substrings Representing 1 To NMedium
Hash TableStringBit Manipulation
Solve →
328Single-Row KeyboardEasy
Hash TableString
Solve →
329Alphabet Board PathMedium
Hash TableString
Solve →
330Largest Color Value in a Directed GraphHard
Hash TableStringDynamic Programming
Solve →
331Number of Wonderful SubstringsMedium
Hash TableStringBit Manipulation
Solve →
332Check if Number Has Equal Digit Count and Digit ValueEasy
Hash TableStringCounting
Solve →
333Repeated DNA SequencesMedium
Hash TableStringBit Manipulation
Solve →
334Design TwitterMedium
Hash TableLinked ListDesign
Solve →
335Design Task ManagerMedium
Hash TableDesignHeap (Priority Queue)
Solve →
336Strobogrammatic NumberEasy
Hash TableTwo PointersString
Solve →
337Longest Substring with At Most K Distinct CharactersMedium
Hash TableStringSliding Window
Solve →
338Brace Expansion IIHard
Hash TableStringBacktracking
Solve →
339Find Root of N-Ary TreeMedium
Hash TableBit ManipulationTree
Solve →
340Throne InheritanceMedium
Hash TableTreeDepth-First Search
Solve →
341Longest Uploaded PrefixMedium
Hash TableBinary SearchUnion-Find
Solve →
342Make Number of Distinct Characters EqualMedium
Hash TableStringCounting
Solve →
343Count K-Subsequences of a String With Maximum BeautyHard
Hash TableMathString
Solve →
344Find Longest Special Substring That Occurs Thrice IIMedium
Hash TableStringBinary Search
Solve →
345Minimum Number of Operations to Make Word K-PeriodicMedium
Hash TableStringCounting
Solve →
346Longest Substring with At Least K Repeating CharactersMedium
Hash TableStringDivide and Conquer
Solve →
347Partition StringMedium
Hash TableStringTrie
Solve →
348Reordered Power of 2Medium
Hash TableMathSorting
Solve →
349Palindrome PermutationEasy
Hash TableStringBit Manipulation
Solve →
350Random Flip MatrixMedium
Hash TableMathReservoir Sampling
Solve →
351String Transforms Into Another StringHard
Hash TableStringGraph Theory
Solve →
352Find Elements in a Contaminated Binary TreeMedium
Hash TableTreeDepth-First Search
Solve →
353Check If Two Expression Trees are EquivalentMedium
Hash TableTreeDepth-First Search
Solve →
354Correct a Binary TreeMedium
Hash TableTreeDepth-First Search
Solve →
355Change Minimum Characters to Satisfy One of Three ConditionsMedium
Hash TableStringCounting
Solve →
356Count Pairs of Equal Substrings With Minimum DifferenceMedium
Hash TableStringGreedy
Solve →
357Design Video Sharing PlatformHard
Hash TableDesignHeap (Priority Queue)
Solve →
358Rings and RodsEasy
Hash TableString
Solve →
359Determine if Two Strings Are CloseMedium
Hash TableStringSorting
Solve →
360Check if the Sentence Is PangramEasy
Hash TableString
Solve →
361Minimum Genetic MutationMedium
Hash TableStringBreadth-First Search
Solve →
362Ugly Number IIMedium
Hash TableMathDynamic Programming
Solve →
363Partition LabelsMedium
Hash TableTwo PointersString
Solve →
364Lowest Common Ancestor of a Binary Tree IIIMedium
Hash TableTwo PointersTree
Solve →
365Next Greater Numerically Balanced NumberMedium
Hash TableMathBacktracking
Solve →
366Lowest Common Ancestor of Deepest LeavesMedium
Hash TableTreeDepth-First Search
Solve →
367Count Largest GroupEasy
Hash TableMathCounting
Solve →
368Minimum Number of Steps to Make Two Strings AnagramMedium
Hash TableStringCounting
Solve →
369Smallest Number in Infinite SetMedium
Hash TableDesignHeap (Priority Queue)
Solve →
370Cousins in Binary Tree IIMedium
Hash TableTreeDepth-First Search
Solve →
371Take K of Each Character From Left and RightMedium
Hash TableStringSliding Window
Solve →
372Construct String With Repeat LimitMedium
Hash TableStringGreedy
Solve →
373Construct K Palindrome StringsMedium
Hash TableStringGreedy
Solve →
374Find the Count of Good IntegersHard
Hash TableMathCombinatorics
Solve →
375Count Vowel Substrings of a StringEasy
Hash TableString
Solve →
376Longest Subsequence Repeated k TimesHard
Hash TableTwo PointersString
Solve →
377Remove Letter To Equalize FrequencyEasy
Hash TableStringCounting
Solve →
378Design In-Memory File SystemHard
Hash TableStringDesign
Solve →
379Design File SystemMedium
Hash TableStringDesign
Solve →
380Find the Longest Substring Containing Vowels in Even CountsMedium
Hash TableStringBit Manipulation
Solve →
381Uncommon Words from Two SentencesEasy
Hash TableStringCounting
Solve →
382Total Characters in String After Transformations IIHard
Hash TableMathString
Solve →
383Reconstruct Original Digits from EnglishMedium
Hash TableMathString
Solve →
384Custom Sort StringMedium
Hash TableStringSorting
Solve →
385Find Most Frequent Vowel and ConsonantEasy
Hash TableStringCounting
Solve →
386Lexicographically Minimum String After Removing StarsMedium
Hash TableStringStack
Solve →
387Maximum Number of Words You Can TypeEasy
Hash TableString
Solve →
388Longest Balanced Substring IIMedium
Hash TableStringPrefix Sum
Solve →
389Count the Number of Special Characters IIMedium
Hash TableString
Solve →
390Path CrossingEasy
Hash TableString
Solve →
391Amount of Time for Binary Tree to Be InfectedMedium
Hash TableTreeDepth-First Search
Solve →
392Longest Nice SubstringEasy
Hash TableStringDivide and Conquer
Solve →
393Basic Calculator IVHard
Hash TableMathString
Solve →
394Count the Number of Special Characters IEasy
Hash TableString
Solve →
395Tweet Counts Per FrequencyMedium
Hash TableStringBinary Search
Solve →
396Check if One String Swap Can Make Strings EqualEasy
Hash TableStringCounting
Solve →
397Parse Lisp ExpressionHard
Hash TableStringStack
Solve →
398Decode the MessageEasy
Hash TableString
Solve →
399Smallest Subtree with all the Deepest NodesMedium
Hash TableTreeDepth-First Search
Solve →
400Data Stream as Disjoint IntervalsHard
Hash TableBinary SearchUnion-Find
Solve →
401HTML Entity ParserMedium
Hash TableString
Solve →
402Swap For Longest Repeated Character SubstringMedium
Hash TableStringSliding Window
Solve →
403Total Appeal of A StringHard
Hash TableStringDynamic Programming
Solve →
404Total Characters in String After Transformations IMedium
Hash TableMathString
Solve →
405Design Underground SystemMedium
Hash TableStringDesign
Solve →
406Maximum Difference Between Even and Odd Frequency IEasy
Hash TableStringCounting
Solve →
407Maximum Frequency StackHard
Hash TableStackDesign
Solve →
408Design A LeaderboardMedium
Hash TableDesignSorting
Solve →
409Design Auction SystemMedium
Hash TableDesignHeap (Priority Queue)
Solve →
410Check if Strings Can be Made Equal With Operations IIMedium
Hash TableStringSorting
Solve →
411Minimum Deletions to Make Character Frequencies UniqueMedium
Hash TableStringGreedy
Solve →
412Optimal Partition of StringMedium
Hash TableStringGreedy
Solve →
413Remove Zero Sum Consecutive Nodes from Linked ListMedium
Hash TableLinked List
Solve →
414Count Substrings With K-Frequency Characters IMedium
Hash TableStringSliding Window
Solve →
415Minimum Operations to Make Character Frequencies EqualHard
Hash TableStringDynamic Programming
Solve →
416Check if All Characters Have Equal Number of OccurrencesEasy
Hash TableStringCounting
Solve →
417Minimum Deletions to Make String K-SpecialMedium
Hash TableStringGreedy
Solve →
418Increasing Decreasing StringEasy
Hash TableStringCounting
Solve →
419Map Sum PairsMedium
Hash TableStringDesign
Solve →
420Find Mirror Score of a StringMedium
Hash TableStringStack
Solve →
421Minimize String LengthEasy
Hash TableString
Solve →
422Lexicographically Smallest Permutation Greater Than TargetMedium
Hash TableStringGreedy
Solve →
423Find Valid Pair of Adjacent Digits in StringEasy
Hash TableStringCounting
Solve →
424Minimum Deletions for At Most K Distinct CharactersEasy
Hash TableStringGreedy
Solve →
425Count Paths That Can Form a Palindrome in a TreeHard
Hash TableBit ManipulationTree
Solve →
426Count Residue PrefixesEasy
Hash TableString
Solve →
427Dinner Plate StacksHard
Hash TableStackDesign
Solve →
428Longest Balanced Substring IMedium
Hash TableStringCounting
Solve →
429Second Largest Digit in a StringEasy
Hash TableString
Solve →
430Random Pick IndexMedium
Hash TableMathReservoir Sampling
Solve →
431Longest Balanced Substring After One SwapMedium
Hash TableStringPrefix Sum
Solve →
432Maximum Number of BalloonsEasy
Hash TableStringCounting
Solve →
433Maximum Number of Occurrences of a SubstringMedium
Hash TableStringSliding Window
Solve →