Medium LeetCode Problems: Page 7 of 8

Problems 1,201 to 1,400 of the 1,579 Medium-rated problems in this library, continuing the list on the Medium hub.

Page 7 of 8

Medium problems, page 7
No.	Problem	Topics
0251	Flatten 2D VectorPremium	Design, Array, Two Pointers +1
0253	Meeting Rooms IIPremium	Greedy, Array, Two Pointers +3
0254	Factor CombinationsPremium	Backtracking
0255	Verify Preorder Sequence in Binary Search TreePremium	Stack, Tree, Binary Search Tree +4
0256	Paint HousePremium	Array, Dynamic Programming
0259	3Sum SmallerPremium	Array, Two Pointers, Binary Search +1
0261	Graph Valid TreePremium	Depth-First Search, Breadth-First Search, Union Find +1
0267	Palindrome Permutation IIPremium	Hash Table, String, Backtracking
0271	Encode and Decode StringsPremium	Design, Array, String
0276	Paint FencePremium	Dynamic Programming
0277	Find the CelebrityPremium	Graph, Two Pointers, Interactive
0280	Wiggle SortPremium	Greedy, Array, Sorting
0281	Zigzag IteratorPremium	Design, Queue, Array +1
0285	Inorder Successor in BSTPremium	Tree, Depth-First Search, Binary Search Tree +1
0286	Walls and GatesPremium	Breadth-First Search, Array, Matrix
0288	Unique Word AbbreviationPremium	Design, Array, Hash Table +1
0291	Word Pattern IIPremium	Hash Table, String, Backtracking
0294	Flip Game IIPremium	Memoization, Math, Dynamic Programming +2
0298	Binary Tree Longest Consecutive SequencePremium	Tree, Depth-First Search, Binary Tree
0308	Range Sum Query 2D - MutablePremium	Design, Binary Indexed Tree, Segment Tree +2
0311	Sparse Matrix MultiplicationPremium	Array, Hash Table, Matrix
0314	Binary Tree Vertical Order TraversalPremium	Tree, Depth-First Search, Breadth-First Search +3
0320	Generalized AbbreviationPremium	Bit Manipulation, String, Backtracking
0323	Number of Connected Components in an Undirected GraphPremium	Depth-First Search, Breadth-First Search, Union Find +1
0325	Maximum Size Subarray Sum Equals kPremium	Array, Hash Table, Prefix Sum
0333	Largest BST SubtreePremium	Tree, Depth-First Search, Binary Search Tree +2
0339	Nested List Weight SumPremium	Depth-First Search, Breadth-First Search
0340	Longest Substring with At Most K Distinct CharactersPremium	Hash Table, String, Sliding Window
0348	Design Tic-Tac-ToePremium	Design, Array, Hash Table +2
0351	Android Unlock PatternsPremium	Bit Manipulation, Dynamic Programming, Backtracking +1
0353	Design Snake GamePremium	Design, Queue, Array +2
0356	Line ReflectionPremium	Array, Hash Table, Math
0360	Sort Transformed ArrayPremium	Array, Math, Two Pointers +1
0361	Bomb EnemyPremium	Array, Dynamic Programming, Matrix
0362	Design Hit CounterPremium	Design, Queue, Array +2
0364	Nested List Weight Sum IIPremium	Stack, Depth-First Search, Breadth-First Search
0366	Find Leaves of Binary TreePremium	Tree, Depth-First Search, Binary Tree
0369	Plus One Linked ListPremium	Linked List, Math
0370	Range AdditionPremium	Array, Prefix Sum
0379	Design Phone DirectoryPremium	Design, Queue, Array +2
0418	Sentence Screen FittingPremium	Array, String, Dynamic Programming
0426	Convert Binary Search Tree to Sorted Doubly Linked ListPremium	Stack, Tree, Depth-First Search +4
0439	Ternary Expression ParserPremium	Stack, Recursion, String
0444	Sequence ReconstructionPremium	Graph, Topological Sort, Array
0469	Convex PolygonPremium	Geometry, Array, Math
0484	Find PermutationPremium	Stack, Greedy, Array +1
0487	Max Consecutive Ones IIPremium	Array, Dynamic Programming, Sliding Window
0490	The MazePremium	Depth-First Search, Breadth-First Search, Array +1
0505	The Maze IIPremium	Depth-First Search, Breadth-First Search, Graph +4
0510	Inorder Successor in BST IIPremium	Tree, Binary Search Tree, Binary Tree
0531	Lonely Pixel IPremium	Array, Hash Table, Matrix
0533	Lonely Pixel IIPremium	Array, Hash Table, Matrix
0534	Game Play Analysis IIIPremium	Database
0536	Construct Binary Tree from StringPremium	Stack, Tree, Depth-First Search +2
0544	Output Contest MatchesPremium	Recursion, String, Simulation
0545	Boundary of Binary TreePremium	Tree, Depth-First Search, Binary Tree
0549	Binary Tree Longest Consecutive Sequence IIPremium	Tree, Depth-First Search, Binary Tree
0555	Split Concatenated StringsPremium	Greedy, Array, String
0562	Longest Line of Consecutive One in MatrixPremium	Array, Dynamic Programming, Matrix
0573	Squirrel SimulationPremium	Array, Math
0574	Winning CandidatePremium	Database
0578	Get Highest Answer Rate QuestionPremium	Database
0580	Count Student Number in DepartmentsPremium	Database
0582	Kill ProcessPremium	Tree, Depth-First Search, Breadth-First Search +2
0612	Shortest Distance in a PlanePremium	Database
0614	Second Degree FollowerPremium	Database
0616	Add Bold Tag in StringPremium	Trie, Array, Hash Table +2
0625	Minimum FactorizationPremium	Greedy, Math
0634	Find the Derangement of An ArrayPremium	Math, Dynamic Programming, Combinatorics
0635	Design Log Storage SystemPremium	Design, Hash Table, String +1
0651	4 Keys KeyboardPremium	Math, Dynamic Programming
0663	Equal Tree PartitionPremium	Tree, Depth-First Search, Binary Tree
0666	Path Sum IVPremium	Tree, Depth-First Search, Array +2
0681	Next Closest TimePremium	Hash Table, String, Backtracking +1
0694	Number of Distinct IslandsPremium	Depth-First Search, Breadth-First Search, Union Find +2
0702	Search in a Sorted Array of Unknown SizePremium	Array, Binary Search, Interactive
0708	Insert into a Sorted Circular Linked ListPremium	Linked List
0723	Candy CrushPremium	Array, Two Pointers, Matrix +1
0737	Sentence Similarity IIPremium	Depth-First Search, Breadth-First Search, Union Find +3
0742	Closest Leaf in a Binary TreePremium	Tree, Depth-First Search, Breadth-First Search +1
0750	Number Of Corner RectanglesPremium	Array, Math, Dynamic Programming +1
0751	IP to CIDRPremium	Bit Manipulation, String
0755	Pour WaterPremium	Array, Simulation
0758	Bold Words in StringPremium	Trie, Array, Hash Table +2
0776	Split BSTPremium	Tree, Binary Search Tree, Recursion +1
0957	Prison Cells After N Days	Bit Manipulation, Array, Hash Table +1
1045	Customers Who Bought All Products	Database
1055	Shortest Way to Form StringPremium	Greedy, Two Pointers, String +1
1057	Campus BikesPremium	Array, Sorting, Heap (Priority Queue)
1058	Minimize Rounding Error to Meet TargetPremium	Greedy, Array, Math +2
1059	All Paths from Source Lead to DestinationPremium	Graph, Topological Sort
1060	Missing Element in Sorted ArrayPremium	Array, Binary Search
1062	Longest Repeating SubstringPremium	String, Binary Search, Dynamic Programming +3
1066	Campus Bikes IIPremium	Bit Manipulation, Array, Dynamic Programming +2
1070	Product Sales Analysis III	Database
1077	Project Employees IIIPremium	Database
1087	Brace ExpansionPremium	Stack, Breadth-First Search, String +2
1098	Unpopular BooksPremium	Database
1100	Find K-Length Substrings With No Repeated CharactersPremium	Hash Table, String, Sliding Window
1101	The Earliest Moment When Everyone Become FriendsPremium	Union Find, Array, Sorting
1102	Path With Maximum Minimum ValuePremium	Depth-First Search, Breadth-First Search, Union Find +4
1107	New Users Daily CountPremium	Database
1112	Highest Grade For Each StudentPremium	Database
1120	Maximum Average SubtreePremium	Tree, Depth-First Search, Binary Tree
1126	Active BusinessesPremium	Database
1132	Reported Posts IIPremium	Database
1135	Connecting Cities With Minimum CostPremium	Union Find, Graph, Minimum Spanning Tree +1
1136	Parallel CoursesPremium	Graph, Topological Sort
1149	Article Views IIPremium	Database
1151	Minimum Swaps to Group All 1's TogetherPremium	Array, Sliding Window
1152	Analyze User Website Visit PatternPremium	Array, Hash Table, String +1
1158	Market Analysis I	Database
1164	Product Price at a Given Date	Database
1166	Design File SystemPremium	Design, Trie, Hash Table +1
1167	Minimum Cost to Connect SticksPremium	Greedy, Array, Heap (Priority Queue)
1174	Immediate Food Delivery II	Database
1181	Before and After PuzzlePremium	Array, Hash Table, String +1
1182	Shortest Distance to Target ColorPremium	Array, Binary Search, Dynamic Programming
1188	Design Bounded Blocking QueuePremium	Concurrency
1193	Monthly Transactions I	Database
1195	Fizz Buzz Multithreaded	Concurrency
1197	Minimum Knight MovesPremium	Breadth-First Search
1198	Find Smallest Common Element in All RowsPremium	Array, Hash Table, Binary Search +2
1204	Last Person to Fit in the Bus	Database
1205	Monthly Transactions IIPremium	Database
1212	Team Scores in Football TournamentPremium	Database
1214	Two Sum BSTsPremium	Stack, Tree, Depth-First Search +4
1215	Stepping NumbersPremium	Breadth-First Search, Math, Backtracking
1226	The Dining Philosophers	Concurrency
1229	Meeting SchedulerPremium	Array, Two Pointers, Sorting
1230	Toss Strange CoinsPremium	Array, Math, Dynamic Programming +1
1236	Web CrawlerPremium	Depth-First Search, Breadth-First Search, String +1
1242	Web Crawler MultithreadedPremium	Depth-First Search, Breadth-First Search, Concurrency
1244	Design A LeaderboardPremium	Design, Hash Table, Sorting
1245	Tree DiameterPremium	Tree, Depth-First Search, Breadth-First Search +2
1256	Encode NumberPremium	Bit Manipulation, Math, String
1257	Smallest Common RegionPremium	Tree, Depth-First Search, Breadth-First Search +3
1258	Synonymous SentencesPremium	Sort, Union Find, Array +3
1264	Page RecommendationsPremium	Database
1265	Print Immutable Linked List in ReversePremium	Stack, Recursion, Linked List +1
1270	All People Report to the Given ManagerPremium	Database
1272	Remove IntervalPremium	Array
1273	Delete Tree NodesPremium	Tree, Depth-First Search, Breadth-First Search +1
1285	Find the Start and End Number of Continuous RangesPremium	Database
1308	Running Total for Different GendersPremium	Database
1321	Restaurant Growth	Database
1341	Movie Rating	Database
1355	Activity ParticipantsPremium	Database
1364	Number of Trusted Contacts of a CustomerPremium	Database
1393	Capital Gain/Loss	Database
1398	Customers Who Bought Products A and B but Not CPremium	Database
1428	Leftmost Column with at Least a OnePremium	Array, Binary Search, Interactive +1
1429	First Unique NumberPremium	Design, Queue, Array +2
1430	Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary TreePremium	Tree, Depth-First Search, Breadth-First Search +1
1440	Evaluate Boolean ExpressionPremium	Database
1445	Apples & OrangesPremium	Database
1454	Active UsersPremium	Database
1459	Rectangles AreaPremium	Database
1468	Calculate SalariesPremium	Database
1485	Clone Binary Tree With Random PointerPremium	Tree, Depth-First Search, Breadth-First Search +2
1490	Clone N-ary TreePremium	Tree, Depth-First Search, Breadth-First Search +1
1500	Design a File Sharing SystemPremium	Design, Hash Table, Data Stream +2
1501	Countries You Can Safely Invest InPremium	Database
1506	Find Root of N-Ary TreePremium	Bit Manipulation, Tree, Depth-First Search +1
1522	Diameter of N-Ary TreePremium	Tree, Depth-First Search
1532	The Most Recent Three OrdersPremium	Database
1533	Find the Index of the Large IntegerPremium	Array, Binary Search, Interactive
1538	Guess the Majority in a Hidden ArrayPremium	Array, Math, Interactive
1549	The Most Recent Orders for Each ProductPremium	Database
1554	Strings Differ by One CharacterPremium	Hash Table, String, Hash Function +1
1555	Bank Account SummaryPremium	Database
1564	Put Boxes Into the Warehouse IPremium	Greedy, Array, Sorting
1570	Dot Product of Two Sparse VectorsPremium	Design, Array, Hash Table +1
1580	Put Boxes Into the Warehouse IIPremium	Greedy, Array, Sorting
1586	Binary Search Tree Iterator IIPremium	Stack, Tree, Design +3
1596	The Most Frequently Ordered Products for Each CustomerPremium	Database
1602	Find Nearest Right Node in Binary TreePremium	Tree, Breadth-First Search, Binary Tree
1612	Check If Two Expression Trees are EquivalentPremium	Tree, Depth-First Search, Hash Table +2
1613	Find the Missing IDsPremium	Database
1618	Maximum Font to Fit a Sentence in a ScreenPremium	Array, String, Binary Search +1
1628	Design an Expression Tree With Evaluate FunctionPremium	Stack, Tree, Design +3
1634	Add Two Polynomials Represented as Linked ListsPremium	Linked List, Math, Two Pointers
1644	Lowest Common Ancestor of a Binary Tree IIPremium	Tree, Depth-First Search, Binary Tree
1650	Lowest Common Ancestor of a Binary Tree IIIPremium	Tree, Hash Table, Two Pointers +1
1660	Correct a Binary TreePremium	Tree, Depth-First Search, Breadth-First Search +2
1666	Change the Root of a Binary TreePremium	Tree, Depth-First Search, Binary Tree
1676	Lowest Common Ancestor of a Binary Tree IVPremium	Tree, Depth-First Search, Hash Table +1
1682	Longest Palindromic Subsequence IIPremium	String, Dynamic Programming
1698	Number of Distinct Substrings in a StringPremium	Trie, String, Suffix Array +2
1699	Number of Calls Between Two PersonsPremium	Database
1709	Biggest Window Between VisitsPremium	Database
1715	Count Apples and OrangesPremium	Database
1730	Shortest Path to Get FoodPremium	Breadth-First Search, Array, Matrix
1740	Find Distance in a Binary TreePremium	Tree, Depth-First Search, Breadth-First Search +2
1746	Maximum Subarray Sum After One OperationPremium	Array, Dynamic Programming
1747	Leetflex Banned AccountsPremium	Database
1756	Design Most Recently Used QueuePremium	Design, Array, Linked List +3
1762	Buildings With an Ocean ViewPremium	Stack, Array, Monotonic Stack
1772	Sort Features by PopularityPremium	Array, Hash Table, String +1
1778	Shortest Path in a Hidden GridPremium	Depth-First Search, Breadth-First Search, Array +2

Problems with a complete Python solution are listed first, then by ascending problem number. Or go by technique instead: all LeetCode patterns.