Medium LeetCode Problems: Page 2 of 8

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

Page 2 of 8

Medium problems, page 2
No.	Problem	Topics
0433	Minimum Genetic Mutation	Breadth-First Search, Hash Table, String
0435	Non-overlapping Intervals	Greedy, Array, Dynamic Programming +1
0436	Find Right Interval	Array, Binary Search, Sorting
0437	Path Sum III	Tree, Depth-First Search, Binary Tree
0438	Find All Anagrams in a String	Hash Table, String, Sliding Window
0442	Find All Duplicates in an Array	Array, Hash Table, Sorting
0443	String Compression	Two Pointers, String
0445	Add Two Numbers II	Stack, Linked List, Math
0447	Number of Boomerangs	Array, Hash Table, Math
0449	Serialize and Deserialize BST	Tree, Depth-First Search, Breadth-First Search +4
0450	Delete Node in a BST	Tree, Binary Search Tree, Binary Tree
0451	Sort Characters By Frequency	Hash Table, String, Bucket Sort +3
0452	Minimum Number of Arrows to Burst Balloons	Greedy, Array, Sorting
0453	Minimum Moves to Equal Array Elements	Array, Math
0454	4Sum II	Array, Hash Table
0456	132 Pattern	Stack, Array, Binary Search +2
0457	Circular Array Loop	Array, Hash Table, Two Pointers
0462	Minimum Moves to Equal Array Elements II	Array, Math, Sorting
0464	Can I Win	Bit Manipulation, Memoization, Math +3
0467	Unique Substrings in Wraparound String	String, Dynamic Programming
0468	Validate IP Address	String
0470	Implement Rand10() Using Rand7()	Math, Rejection Sampling, Probability and Statistics +1
0473	Matchsticks to Square	Bit Manipulation, Array, Dynamic Programming +2
0474	Ones and Zeroes	Array, String, Dynamic Programming
0475	Heaters	Array, Two Pointers, Binary Search +1
0477	Total Hamming Distance	Bit Manipulation, Array, Math
0478	Generate Random Point in a Circle	Geometry, Math, Rejection Sampling +1
0481	Magical String	Two Pointers, String
0486	Predict the Winner	Recursion, Array, Math +2
0491	Non-decreasing Subsequences	Bit Manipulation, Array, Hash Table +1
0494	Target Sum	Array, Dynamic Programming, Backtracking
0497	Random Point in Non-overlapping Rectangles	Reservoir Sampling, Array, Math +4
0498	Diagonal Traverse	Array, Matrix, Simulation
0503	Next Greater Element II	Stack, Array, Monotonic Stack
0508	Most Frequent Subtree Sum	Tree, Depth-First Search, Hash Table +1
0513	Find Bottom Left Tree Value	Tree, Depth-First Search, Breadth-First Search +1
0515	Find Largest Value in Each Tree Row	Tree, Depth-First Search, Breadth-First Search +1
0516	Longest Palindromic Subsequence	String, Dynamic Programming
0518	Coin Change II	Array, Dynamic Programming
0519	Random Flip Matrix	Reservoir Sampling, Hash Table, Math +1
0522	Longest Uncommon Subsequence II	Array, Hash Table, Two Pointers +2
0523	Continuous Subarray Sum	Array, Hash Table, Math +1
0524	Longest Word in Dictionary through Deleting	Array, Two Pointers, String +1
0525	Contiguous Array	Array, Hash Table, Prefix Sum
0526	Beautiful Arrangement	Bit Manipulation, Array, Dynamic Programming +2
0528	Random Pick with Weight	Array, Math, Binary Search +2
0529	Minesweeper	Depth-First Search, Breadth-First Search, Array +1
0532	K-diff Pairs in an Array	Array, Hash Table, Two Pointers +2
0535	Encode and Decode TinyURL	Design, Hash Table, String +1
0537	Complex Number Multiplication	Math, String, Simulation
0538	Convert BST to Greater Tree	Tree, Depth-First Search, Binary Search Tree +1
0539	Minimum Time Difference	Array, Math, String +1
0540	Single Element in a Sorted Array	Array, Binary Search
0542	01 Matrix	Breadth-First Search, Array, Dynamic Programming +1
0547	Number of Provinces	Depth-First Search, Breadth-First Search, Union Find +1
0550	Game Play Analysis IV	Database
0553	Optimal Division	Array, Math, Dynamic Programming
0554	Brick Wall	Array, Hash Table
0556	Next Greater Element III	Math, Two Pointers, String
0558	Logical OR of Two Binary Grids Represented as Quad-Trees	Tree, Divide and Conquer
0560	Subarray Sum Equals K	Array, Hash Table, Prefix Sum
0565	Array Nesting	Depth-First Search, Array
0567	Permutation in String	Hash Table, Two Pointers, String +1
0570	Managers with at Least 5 Direct Reports	Database
0576	Out of Boundary Paths	Dynamic Programming
0581	Shortest Unsorted Continuous Subarray	Stack, Greedy, Array +3
0583	Delete Operation for Two Strings	String, Dynamic Programming
0585	Investments in 2016	Database
0592	Fraction Addition and Subtraction	Math, String, Simulation
0593	Valid Square	Geometry, Math
0602	Friend Requests II: Who Has the Most Friends	Database
0606	Construct String from Binary Tree	Tree, Depth-First Search, String +1
0608	Tree Node	Database
0609	Find Duplicate File in System	Array, Hash Table, String
0611	Valid Triangle Number	Greedy, Array, Two Pointers +2
0621	Task Scheduler	Greedy, Array, Hash Table +3
0622	Design Circular Queue	Design, Queue, Array +1
0623	Add One Row to Tree	Tree, Depth-First Search, Breadth-First Search +1
0624	Maximum Distance in Arrays	Greedy, Array
0626	Exchange Seats	Database
0633	Sum of Square Numbers	Math, Two Pointers, Binary Search
0636	Exclusive Time of Functions	Stack, Array
0638	Shopping Offers	Bit Manipulation, Memoization, Array +3
0640	Solve the Equation	Math, String, Simulation
0641	Design Circular Deque	Design, Queue, Array +1
0646	Maximum Length of Pair Chain	Greedy, Array, Dynamic Programming +1
0647	Palindromic Substrings	Two Pointers, String, Dynamic Programming
0648	Replace Words	Trie, Array, Hash Table +1
0649	Dota2 Senate	Greedy, Queue, String
0650	2 Keys Keyboard	Math, Dynamic Programming
0652	Find Duplicate Subtrees	Tree, Depth-First Search, Hash Table +1
0654	Maximum Binary Tree	Stack, Tree, Array +3
0655	Print Binary Tree	Tree, Depth-First Search, Breadth-First Search +1
0658	Find K Closest Elements	Array, Two Pointers, Binary Search +3
0659	Split Array into Consecutive Subsequences	Greedy, Array, Hash Table +1
0662	Maximum Width of Binary Tree	Tree, Depth-First Search, Breadth-First Search +1
0665	Non-decreasing Array	Array
0667	Beautiful Arrangement II	Array, Math
0669	Trim a Binary Search Tree	Tree, Depth-First Search, Binary Search Tree +1
0670	Maximum Swap	Greedy, Math
0672	Bulb Switcher II	Bit Manipulation, Depth-First Search, Breadth-First Search +1
0673	Number of Longest Increasing Subsequence	Binary Indexed Tree, Segment Tree, Array +1
0676	Implement Magic Dictionary	Depth-First Search, Design, Trie +2
0677	Map Sum Pairs	Design, Trie, Hash Table +1
0678	Valid Parenthesis String	Stack, Greedy, String +1
0684	Redundant Connection	Depth-First Search, Breadth-First Search, Union Find +1
0686	Repeated String Match	String, String Matching
0687	Longest Univalue Path	Tree, Depth-First Search, Binary Tree
0688	Knight Probability in Chessboard	Dynamic Programming
0690	Employee Importance	Tree, Depth-First Search, Breadth-First Search +2
0692	Top K Frequent Words	Trie, Array, Hash Table +5
0695	Max Area of Island	Depth-First Search, Breadth-First Search, Union Find +2
0698	Partition to K Equal Sum Subsets	Bit Manipulation, Memoization, Array +3
0701	Insert into a Binary Search Tree	Tree, Binary Search Tree, Binary Tree
0707	Design Linked List	Design, Linked List
0712	Minimum ASCII Delete Sum for Two Strings	String, Dynamic Programming
0713	Subarray Product Less Than K	Array, Binary Search, Prefix Sum +1
0714	Best Time to Buy and Sell Stock with Transaction Fee	Greedy, Array, Dynamic Programming
0718	Maximum Length of Repeated Subarray	Array, Binary Search, Dynamic Programming +3
0720	Longest Word in Dictionary	Trie, Array, Hash Table +2
0721	Accounts Merge	Depth-First Search, Breadth-First Search, Union Find +4
0722	Remove Comments	Array, String
0725	Split Linked List in Parts	Linked List
0729	My Calendar I	Design, Segment Tree, Array +2
0731	My Calendar II	Design, Segment Tree, Array +3
0735	Asteroid Collision	Stack, Array, Simulation
0738	Monotone Increasing Digits	Greedy, Math
0739	Daily Temperatures	Stack, Array, Monotonic Stack
0740	Delete and Earn	Array, Hash Table, Dynamic Programming
0743	Network Delay Time	Depth-First Search, Breadth-First Search, Graph +2
0752	Open the Lock	Breadth-First Search, Array, Hash Table +1
0754	Reach a Number	Math, Binary Search
0756	Pyramid Transition Matrix	Bit Manipulation, Hash Table, String +1
0763	Partition Labels	Greedy, Hash Table, Two Pointers +1
0764	Largest Plus Sign	Array, Dynamic Programming
0767	Reorganize String	Greedy, Hash Table, String +3
0769	Max Chunks To Make Sorted	Stack, Greedy, Array +2
0775	Global and Local Inversions	Array, Math
0777	Swap Adjacent in LR String	Two Pointers, String
0779	K-th Symbol in Grammar	Bit Manipulation, Recursion, Math
0781	Rabbits in Forest	Greedy, Array, Hash Table +1
0784	Letter Case Permutation	Bit Manipulation, String, Backtracking
0785	Is Graph Bipartite?	Depth-First Search, Breadth-First Search, Union Find +1
0786	K-th Smallest Prime Fraction	Array, Two Pointers, Binary Search +2
0787	Cheapest Flights Within K Stops	Depth-First Search, Breadth-First Search, Graph +3
0788	Rotated Digits	Math, Dynamic Programming
0789	Escape The Ghosts	Array, Math
0790	Domino and Tromino Tiling	Dynamic Programming
0791	Custom Sort String	Hash Table, String, Sorting
0792	Number of Matching Subsequences	Trie, Array, Hash Table +4
0794	Valid Tic-Tac-Toe State	Array, Matrix
0795	Number of Subarrays with Bounded Maximum	Array, Two Pointers
0797	All Paths From Source to Target	Depth-First Search, Breadth-First Search, Graph +1
0799	Champagne Tower	Dynamic Programming
0802	Find Eventual Safe States	Depth-First Search, Breadth-First Search, Graph +1
0807	Max Increase to Keep City Skyline	Greedy, Array, Matrix
0808	Soup Servings	Math, Dynamic Programming, Probability and Statistics
0809	Expressive Words	Array, Two Pointers, String
0811	Subdomain Visit Count	Array, Hash Table, String +1
0813	Largest Sum of Averages	Array, Dynamic Programming, Prefix Sum
0814	Binary Tree Pruning	Tree, Depth-First Search, Binary Tree
0816	Ambiguous Coordinates	String, Backtracking, Enumeration
0817	Linked List Components	Array, Hash Table, Linked List
0820	Short Encoding of Words	Trie, Array, Hash Table +1
0822	Card Flipping Game	Array, Hash Table
0823	Binary Trees With Factors	Array, Hash Table, Dynamic Programming +1
0825	Friends Of Appropriate Ages	Array, Two Pointers, Binary Search +1
0826	Most Profit Assigning Work	Greedy, Array, Two Pointers +2
0831	Masking Personal Information	String
0833	Find And Replace in String	Array, Hash Table, String +1
0835	Image Overlap	Array, Matrix
0837	New 21 Game	Math, Dynamic Programming, Sliding Window +1
0838	Push Dominoes	Two Pointers, String, Dynamic Programming
0840	Magic Squares In Grid	Array, Hash Table, Math +1
0841	Keys and Rooms	Depth-First Search, Breadth-First Search, Graph
0842	Split Array into Fibonacci Sequence	String, Backtracking
0845	Longest Mountain in Array	Array, Two Pointers, Dynamic Programming +1
0846	Hand of Straights	Greedy, Array, Hash Table +1
0848	Shifting Letters	Array, String, Prefix Sum
0849	Maximize Distance to Closest Person	Array
0851	Loud and Rich	Depth-First Search, Graph, Topological Sort +1
0852	Peak Index in a Mountain Array	Array, Binary Search
0853	Car Fleet	Stack, Array, Sorting +1
0855	Exam Room	Design, Ordered Set, Heap (Priority Queue)
0856	Score of Parentheses	Stack, String
0858	Mirror Reflection	Geometry, Math, Number Theory
0861	Score After Flipping Matrix	Greedy, Bit Manipulation, Array +1
0863	All Nodes Distance K in Binary Tree	Tree, Depth-First Search, Breadth-First Search +2
0865	Smallest Subtree with all the Deepest Nodes	Tree, Depth-First Search, Breadth-First Search +2
0866	Prime Palindrome	Math, Number Theory
0869	Reordered Power of 2	Hash Table, Math, Counting +2
0870	Advantage Shuffle	Greedy, Array, Two Pointers +1
0873	Length of Longest Fibonacci Subsequence	Array, Hash Table, Dynamic Programming
0874	Walking Robot Simulation	Array, Hash Table, Simulation
0875	Koko Eating Bananas	Array, Binary Search
0877	Stone Game	Array, Math, Dynamic Programming +1
0880	Decoded String at Index	Stack, String
0881	Boats to Save People	Greedy, Array, Two Pointers +1
0885	Spiral Matrix III	Array, Matrix, Simulation
0886	Possible Bipartition	Depth-First Search, Breadth-First Search, Union Find +1

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