Data Structures and Algorithms

Leetcode Problemset

#	Problem	Difficulty	Topics
1	01 Matrix	Medium	Array, Dynamic Programming, Breadth-First Search, Matrix
2	132 Pattern	Medium	Array, Binary Search, Stack, Monotonic Stack, Ordered Set
3	3Sum	Medium	Array, Two Pointers, Sorting
4	3Sum Closest	Medium	Array, Two Pointers, Sorting
5	3Sum With Multiplicity	Medium	Array, Hash Table, Two Pointers, Sorting, Counting
6	4Sum	Medium	Array, Two Pointers, Sorting
7	4Sum II	Medium	Array, Hash Table
8	Add Strings	Easy	Math, String, Simulation
9	Add Two Numbers	Medium	Linked List, Math, Recursion
10	Add Two Numbers II	Medium	Linked List, Math, Stack
11	All Divisions With the Highest Score of a Binary Array	Medium	Array
12	All Elements in Two Binary Search Trees	Medium	Tree, Depth-First Search, Binary Search Tree, Sorting, Binary Tree
13	All Nodes Distance K in Binary Tree	Medium	Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
14	Ambiguous Coordinates	Medium	String, Backtracking, Enumeration
15	Amount of Time for Binary Tree to Be Infected	Medium	Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
16	Angle Between Hands of a Clock	Medium	Math
17	Arithmetic Slices	Medium	Array, Dynamic Programming, Sliding Window
18	Arithmetic Subarrays	Medium	Array, Hash Table, Sorting
19	Arranging Coins	Easy	Math, Binary Search
20	Array Nesting	Medium	Array, Depth-First Search
21	Array of Doubled Pairs	Medium	Array, Hash Table, Greedy, Sorting
22	Array Partition	Easy	Array, Greedy, Sorting, Counting Sort
23	Backspace String Compare	Easy	Two Pointers, String, Stack, Simulation
24	Basic Calculator	Hard	Math, String, Stack, Recursion
25	Best Time to Buy and Sell Stock	Easy	Array, Dynamic Programming
26	Best Time to Buy and Sell Stock II	Medium	Array, Dynamic Programming, Greedy
27	Best Time to Buy and Sell Stock III	Hard	Array, Dynamic Programming
28	Best Time to Buy and Sell Stock IV	Hard	Array, Dynamic Programming
29	Best Time to Buy and Sell Stock with Cooldown	Medium	Array, Dynamic Programming
30	Best Time to Buy and Sell Stock with Transaction Fee	Medium	Array, Dynamic Programming, Greedy
31	Binary Gap	Easy	Bit Manipulation
32	Binary Search	Easy	Array, Binary Search
33	Binary Search Tree Iterator	Medium	Stack, Tree, Design, Binary Search Tree, Binary Tree, Iterator
34	Binary Tree Cameras	Hard	Dynamic Programming, Tree, Depth-First Search, Binary Tree, DP on Trees
35	Binary Tree Inorder Traversal	Easy	Stack, Tree, Depth-First Search, Binary Tree
36	Binary Tree Level Order Traversal	Medium	Tree, Breadth-First Search, Binary Tree
37	Binary Tree Maximum Path Sum	Hard	Dynamic Programming, Tree, Depth-First Search, Binary Tree, DP on Trees
38	Binary Tree Postorder Traversal	Easy	Stack, Tree, Depth-First Search, Binary Tree
39	Binary Tree Preorder Traversal	Easy	Stack, Tree, Depth-First Search, Binary Tree
40	Binary Tree Right Side View	Medium	Tree, Depth-First Search, Breadth-First Search, Binary Tree
41	Binary Tree Tilt	Easy	Tree, Depth-First Search, Binary Tree, DP on Trees
42	Binary Trees With Factors	Medium	Array, Hash Table, Dynamic Programming, Sorting
43	Break a Palindrome	Medium	String, Greedy
44	Broken Calculator	Medium	Math, Greedy
45	Build an Array With Stack Operations	Medium	Array, Stack, Simulation
46	Bus Routes	Hard	Array, Hash Table, Breadth-First Search
47	Candy	Hard	Array, Greedy
48	Capacity To Ship Packages Within D Days	Medium	Array, Binary Search
49	Car Pooling	Medium	Array, Sorting, Heap (Priority Queue), Simulation, Prefix Sum
50	Check if Move is Legal	Medium	Array, Matrix, Enumeration
51	Check If N and Its Double Exist	Easy	Array, Hash Table, Two Pointers, Binary Search, Sorting
52	Check if There Is a Valid Parentheses String Path	Hard	Array, Dynamic Programming, Matrix, Bracket Sequences
53	Climbing Stairs	Easy	Math, Dynamic Programming, Memoization
54	Clone Graph	Medium	Hash Table, Depth-First Search, Breadth-First Search, Graph Theory
55	Closest Subsequence Sum	Hard	Array, Two Pointers, Dynamic Programming, Bit Manipulation, Meet in the Middle, Sorting, Bitmask
56	Coin Change	Medium	Array, Dynamic Programming, Breadth-First Search, Knapsack Problem, Complete Knapsack
57	Coin Change II	Medium	Array, Dynamic Programming, Knapsack Problem, Complete Knapsack
58	Combination Sum	Medium	Array, Backtracking
59	Combination Sum II	Medium	Array, Backtracking
60	Combination Sum III	Medium	Array, Backtracking
61	Combination Sum IV	Medium	Array, Dynamic Programming
62	Compare Version Numbers	Medium	Two Pointers, String
63	Complex Number Multiplication	Medium	Math, String, Simulation
64	Construct Binary Search Tree from Preorder Traversal	Medium	Array, Stack, Tree, Binary Search Tree, Monotonic Stack, Binary Tree
65	Construct Binary Tree from Preorder and Inorder Traversal	Medium	Array, Hash Table, Divide and Conquer, Tree, Binary Tree
66	Construct Target Array With Multiple Sums	Hard	Array, Heap (Priority Queue)
67	Container With Most Water	Medium	Array, Two Pointers, Greedy
68	Contains Duplicate III	Hard	Array, Sliding Window, Sorting, Bucket Sort, Ordered Set
69	Contiguous Array	Medium	Array, Hash Table, Prefix Sum
70	Continuous Subarray Sum	Medium	Array, Hash Table, Math, Prefix Sum, Pigeonhole Principle
71	Convert Sorted Array to Binary Search Tree	Easy	Array, Divide and Conquer, Tree, Binary Search Tree, Binary Tree
72	Convert Sorted List to Binary Search Tree	Medium	Linked List, Divide and Conquer, Tree, Binary Search Tree, Binary Tree
73	Copy List with Random Pointer	Medium	Hash Table, Linked List
74	Count Good Nodes in Binary Tree	Medium	Tree, Depth-First Search, Breadth-First Search, Binary Tree
75	Count Negative Numbers in a Sorted Matrix	Easy	Array, Binary Search, Matrix
76	Count Nice Pairs in an Array	Medium	Array, Hash Table, Math, Counting
77	Count Nodes Equal to Average of Subtree	Medium	Tree, Depth-First Search, Binary Tree
78	Count Number of Homogenous Substrings	Medium	Math, String
79	Count Number of Rectangles Containing Each Point	Medium	Array, Hash Table, Binary Search, Binary Indexed Tree, Sorting
80	Count Number of Texts	Medium	Hash Table, Math, String, Dynamic Programming
81	Count of Smaller Numbers After Self	Hard	Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set, Treap
82	Count Primes	Medium	Array, Math, Enumeration, Number Theory, Primality Test, Sieve Theory, Prime Number Sieve
83	Count Sorted Vowel Strings	Medium	Math, Dynamic Programming, Combinatorics
84	Count Vowels Permutation	Hard	Dynamic Programming
85	Course Schedule	Medium	Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort, Directed Acyclic Graph
86	Course Schedule II	Medium	Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
87	Course Schedule III	Hard	Array, Greedy, Sorting, Heap (Priority Queue)
88	Cousins in Binary Tree	Easy	Tree, Depth-First Search, Breadth-First Search, Binary Tree
89	Critical Connections in a Network	Hard	Depth-First Search, Graph Theory, Biconnected Component, Bridge (Graph)
90	Custom Sort String	Medium	Hash Table, String, Sorting
91	Daily Temperatures	Medium	Array, Stack, Monotonic Stack
92	Decode String	Medium	String, Stack, Recursion
93	Decode Ways	Medium	String, Dynamic Programming
94	Decode Ways II	Hard	String, Dynamic Programming
95	Decode XORed Array	Easy	Array, Bit Manipulation
96	Deepest Leaves Sum	Medium	Tree, Depth-First Search, Breadth-First Search, Binary Tree
97	Delete and Earn	Medium	Array, Hash Table, Dynamic Programming
98	Delete Node in a BST	Medium	Tree, Binary Search Tree, Binary Tree
99	Delete Operation for Two Strings	Medium	String, Dynamic Programming, Longest Common Subsequence
100	Design a Food Rating System	Medium	Array, Hash Table, String, Design, Heap (Priority Queue), Ordered Set
101	Design Add and Search Words Data Structure	Medium	String, Depth-First Search, Design, Trie
102	Design an Ordered Stream	Easy	Array, Hash Table, Design, Data Stream
103	Design Circular Queue	Medium	Array, Linked List, Design, Queue
104	Design Graph With Shortest Path Calculator	Hard	Graph Theory, Design, Heap (Priority Queue), Shortest Path
105	Design HashSet	Easy	Array, Hash Table, Linked List, Design, Hash Function
106	Design In-Memory File System	Hard	Hash Table, String, Design, Trie, Sorting
107	Design Linked List	Medium	Linked List, Design
108	Design Twitter	Medium	Hash Table, Linked List, Design, Heap (Priority Queue)
109	Determine if Two Strings Are Close	Medium	Hash Table, String, Sorting, Counting
110	Determine Whether Matrix Can Be Obtained By Rotation	Easy	Array, Matrix
111	Diagonal Traverse	Medium	Array, Matrix, Simulation
112	Diagonal Traverse II	Medium	Array, Sorting, Heap (Priority Queue)
113	Diameter of Binary Tree	Easy	Tree, Depth-First Search, Binary Tree, DP on Trees
114	Different Ways to Add Parentheses	Medium	Math, String, Dynamic Programming, Recursion, Memoization, Bracket Sequences
115	Divide Two Integers	Medium	Math, Bit Manipulation
116	Dungeon Game	Hard	Array, Dynamic Programming, Matrix
117	Duplicate Zeros	Easy	Array, Two Pointers
118	Edit Distance	Medium	String, Dynamic Programming
119	Eliminate Maximum Number of Monsters	Medium	Array, Greedy, Sorting
120	Evaluate Division	Medium	Array, String, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory, Shortest Path, Bellman–Ford Algorithm, Floyd–Warshall Algorithm
121	Evaluate Reverse Polish Notation	Medium	Array, Math, Stack
122	Expression Add Operators	Hard	Math, String, Backtracking
123	Filling Bookcase Shelves	Medium	Array, Dynamic Programming
124	Find a Corresponding Node of a Binary Tree in a Clone of That Tree	Easy	Tree, Depth-First Search, Breadth-First Search, Binary Tree
125	Find All Anagrams in a String	Medium	Hash Table, String, Sliding Window
126	Find All Duplicates in an Array	Medium	Array, Hash Table, Sorting
127	Find All Numbers Disappeared in an Array	Easy	Array, Hash Table
128	Find All People With Secret	Hard	Depth-First Search, Breadth-First Search, Union-Find, Graph Theory, Sorting
129	Find and Replace Pattern	Medium	Array, Hash Table, String
130	Find Duplicate File in System	Medium	Array, Hash Table, String
131	Find Eventual Safe States	Medium	Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort, Kosaraju's Algorithm, Tarjan's SCC Algorithm
132	Find First and Last Position of Element in Sorted Array	Medium	Array, Binary Search
133	Find in Mountain Array	Hard	Array, Binary Search, Interactive, Ternary Search
134	Find K Closest Elements	Medium	Array, Two Pointers, Binary Search, Sliding Window, Sorting, Heap (Priority Queue)
135	Find Largest Value in Each Tree Row	Medium	Tree, Depth-First Search, Breadth-First Search, Binary Tree
136	Find Median from Data Stream	Hard	Two Pointers, Design, Sorting, Heap (Priority Queue), Data Stream
137	Find Minimum in Rotated Sorted Array	Medium	Array, Binary Search
138	Find Missing Observations	Medium	Array, Math, Simulation
139	Find Mode in Binary Search Tree	Easy	Tree, Depth-First Search, Binary Search Tree, Binary Tree
140	Find Original Array From Doubled Array	Medium	Array, Hash Table, Greedy, Sorting
141	Find Peak Element	Medium	Array, Binary Search
142	Find Pivot Index	Easy	Array, Prefix Sum
143	Find Players With Zero or One Losses	Medium	Array, Hash Table, Sorting, Counting
144	Find Polygon With the Largest Perimeter	Medium	Array, Greedy, Sorting, Prefix Sum, Polygons
145	Find Smallest Letter Greater Than Target	Easy	Array, Binary Search
146	Find Substring With Given Hash Value	Hard	String, Sliding Window, Rolling Hash, Hash Function
147	Find the Celebrity	Medium	Two Pointers, Graph Theory, Interactive
148	Find The Original Array of Prefix Xor	Medium	Array, Bit Manipulation
149	Find the Shortest Superstring	Hard	Array, String, Dynamic Programming, Bit Manipulation, Bitmask, Hamiltonian Path
150	Find the Town Judge	Easy	Array, Hash Table, Graph Theory
151	Find the Winner of an Array Game	Medium	Array, Simulation
152	Find Unique Binary String	Medium	Array, Hash Table, String, Backtracking
153	Find Winner on a Tic Tac Toe Game	Easy	Array, Hash Table, Matrix, Simulation
154	First Bad Version	Easy	Binary Search, Interactive
155	First Missing Positive	Hard	Array, Hash Table
156	First Unique Character in a String	Easy	Hash Table, String, Queue, Counting
157	Flatten a Multilevel Doubly Linked List	Medium	Linked List, Depth-First Search, Doubly-Linked List
158	Flatten Binary Tree to Linked List	Medium	Linked List, Stack, Tree, Depth-First Search, Binary Tree
159	Flatten Nested List Iterator	Medium	Stack, Tree, Depth-First Search, Design, Queue, Iterator
160	Flood Fill	Easy	Array, Depth-First Search, Breadth-First Search, Matrix
161	Frequency of the Most Frequent Element	Medium	Array, Binary Search, Greedy, Sliding Window, Sorting, Prefix Sum
162	Frog Position After T Seconds	Hard	Tree, Depth-First Search, Breadth-First Search, Graph Theory
163	Fruit Into Baskets	Medium	Array, Hash Table, Sliding Window
164	Gas Station	Medium	Array, Greedy
165	Generate Parentheses	Medium	String, Dynamic Programming, Backtracking, Bracket Sequences
166	Graph Connectivity With Threshold	Hard	Array, Math, Union-Find, Number Theory
167	Gray Code	Medium	Math, Backtracking, Bit Manipulation
168	Group Anagrams	Medium	Array, Hash Table, String, Sorting
169	Guess Number Higher or Lower II	Medium	Math, Dynamic Programming, Minimax, Game Theory
170	Happy Number	Easy	Hash Table, Math, Two Pointers, Floyd's Cycle Finding Algorithm
171	House Robber	Medium	Array, Dynamic Programming
172	House Robber II	Medium	Array, Dynamic Programming
173	House Robber III	Medium	Dynamic Programming, Tree, Depth-First Search, Binary Tree, DP on Trees
174	Implement Queue using Stacks	Easy	Stack, Design, Queue
175	Implement Stack using Queues	Easy	Stack, Design, Queue
176	Implement Trie (Prefix Tree)	Medium	Hash Table, String, Design, Trie
177	Inorder Successor in BST	Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree
178	Insert Delete GetRandom O(1)	Medium	Array, Hash Table, Math, Design, Randomized
179	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	Array, Hash Table, Math, Design, Randomized
180	Integer Break	Medium	Math, Dynamic Programming
181	Interleaving String	Medium	String, Dynamic Programming
182	Intersection of Two Arrays II	Easy	Array, Hash Table, Two Pointers, Binary Search, Sorting
183	Intersection of Two Linked Lists	Easy	Hash Table, Linked List, Two Pointers
184	Intervals Between Identical Elements	Medium	Array, Hash Table, Prefix Sum
185	Invert Binary Tree	Easy	Tree, Depth-First Search, Breadth-First Search, Binary Tree
186	Is Graph Bipartite?	Medium	Depth-First Search, Breadth-First Search, Union-Find, Graph Theory, Graph Coloring, Bipartite Graph
187	Island Perimeter	Easy	Array, Depth-First Search, Breadth-First Search, Matrix
188	Isomorphic Strings	Easy	Hash Table, String
189	Jewels and Stones	Easy	Hash Table, String
190	Jump Game	Medium	Array, Dynamic Programming, Greedy
191	Jump Game II	Medium	Array, Dynamic Programming, Greedy
192	Jump Game III	Medium	Array, Depth-First Search, Breadth-First Search
193	K Closest Points to Origin	Medium	Array, Math, Divide and Conquer, Geometry, Sorting, Heap (Priority Queue), Quickselect, K-D Tree
194	K Inverse Pairs Array	Hard	Dynamic Programming
195	K-diff Pairs in an Array	Medium	Array, Hash Table, Two Pointers, Binary Search, Sorting
196	Keys and Rooms	Medium	Depth-First Search, Breadth-First Search, Graph Theory
197	Keys and Rooms	Medium	Depth-First Search, Breadth-First Search, Graph Theory
198	Knight Dialer	Medium	Dynamic Programming
199	Koko Eating Bananas	Medium	Array, Binary Search
200	Kth Missing Positive Number	Easy	Array, Binary Search
201	Kth Smallest Element in a BST	Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree
202	Kth Smallest Element in a Sorted Matrix	Medium	Array, Binary Search, Sorting, Heap (Priority Queue), Matrix
203	Largest Component Size by Common Factor	Hard	Array, Hash Table, Math, Union-Find, Number Theory, Prime Factorization
204	Largest Number	Medium	Array, String, Greedy, Sorting
205	Largest Number At Least Twice of Others	Easy	Array, Sorting
206	Largest Plus Sign	Medium	Array, Dynamic Programming
207	Largest Rectangle in Histogram	Hard	Array, Stack, Monotonic Stack, Range Minimum/Maximum Query
208	Largest Submatrix With Rearrangements	Medium	Array, Greedy, Sorting, Matrix
209	Largest Values From Labels	Medium	Array, Hash Table, Greedy, Sorting, Counting
210	Last Moment Before All Ants Fall Out of a Plank	Medium	Array, Brainteaser, Simulation
211	License Key Formatting	Easy	String
212	Linked List Cycle	Easy	Hash Table, Linked List, Two Pointers, Floyd's Cycle Finding Algorithm
213	Linked List Cycle II	Medium	Hash Table, Linked List, Two Pointers, Floyd's Cycle Finding Algorithm
214	Longest Common Prefix	Easy	Array, String, Trie
215	Longest Consecutive Sequence	Medium	Array, Hash Table, Union-Find
216	Longest Duplicate Substring	Hard	String, Binary Search, Sliding Window, Rolling Hash, Suffix Array, Hash Function, Suffix Automaton, Suffix Tree, Z Algorithm, Boyer–Moore String-Search Algorithm
217	Longest Increasing Path in a Matrix	Hard	Array, Dynamic Programming, Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort, Memoization, Matrix, Directed Acyclic Graph
218	Longest Increasing Subsequence	Medium	Array, Binary Search, Dynamic Programming, Longest Increasing Subsequence
219	Longest Palindromic Subsequence	Medium	String, Dynamic Programming
220	Longest Palindromic Substring	Medium	Two Pointers, String, Dynamic Programming, Manacher
221	Longest Repeating Character Replacement	Medium	Hash Table, String, Sliding Window
222	Longest String Chain	Medium	Array, Hash Table, Two Pointers, String, Dynamic Programming, Sorting
223	Longest Substring with At Least K Repeating Characters	Medium	Hash Table, String, Divide and Conquer, Sliding Window
224	Longest Substring Without Repeating Characters	Medium	Hash Table, String, Sliding Window
225	Longest Turbulent Subarray	Medium	Array, Dynamic Programming, Sliding Window
226	Longest Uncommon Subsequence II	Medium	Array, Hash Table, Two Pointers, String, Sorting
227	Longest Valid Parentheses	Hard	String, Dynamic Programming, Stack, Bracket Sequences
228	Lowest Common Ancestor of a Binary Search Tree	Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree, Binary Lifting, Lowest Common Ancestor
229	Lowest Common Ancestor of a Binary Tree	Medium	Tree, Depth-First Search, Binary Tree, Binary Lifting, Lowest Common Ancestor
230	LRU Cache	Medium	Hash Table, Linked List, Design, Doubly-Linked List
231	Majority Element	Easy	Array, Hash Table, Divide and Conquer, Sorting, Counting, Boyer–Moore Majority Vote Algorithm
232	Majority Element II	Medium	Array, Hash Table, Sorting, Counting, Boyer–Moore Majority Vote Algorithm
233	Making File Names Unique	Medium	Array, Hash Table, String
234	Map Sum Pairs	Medium	Hash Table, String, Design, Trie
235	Matchsticks to Square	Medium	Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
236	Max Area of Island	Medium	Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
237	Max Consecutive Ones III	Medium	Array, Binary Search, Sliding Window, Prefix Sum
238	Max Number of K-Sum Pairs	Medium	Array, Hash Table, Two Pointers, Sorting
239	Max Sum of Rectangle No Larger Than K	Hard	Array, Binary Search, Matrix, Prefix Sum, Ordered Set
240	Maximal Rectangle	Hard	Array, Dynamic Programming, Stack, Matrix, Monotonic Stack
241	Maximal Square	Medium	Array, Dynamic Programming, Matrix
242	Maximize Distance to Closest Person	Medium	Array
243	Maximize the Confusion of an Exam	Medium	String, Binary Search, Sliding Window, Prefix Sum
244	Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts	Medium	Array, Greedy, Sorting
245	Maximum Depth of Binary Tree	Easy	Tree, Depth-First Search, Breadth-First Search, Binary Tree
246	Maximum Difference Between Node and Ancestor	Medium	Tree, Depth-First Search, Binary Tree
247	Maximum Earnings From Taxi	Medium	Array, Hash Table, Binary Search, Dynamic Programming, Sorting
248	Maximum Element After Decreasing and Rearranging	Medium	Array, Greedy, Sorting
249	Maximum Erasure Value	Medium	Array, Hash Table, Sliding Window
250	Maximum Frequency Stack	Hard	Hash Table, Stack, Design, Ordered Set
251	Maximum Gap	Medium	Array, Sorting, Bucket Sort, Radix Sort, Pigeonhole Principle
252	Maximum Length of a Concatenated String with Unique Characters	Medium	Array, String, Backtracking, Bit Manipulation
253	Maximum Length of Repeated Subarray	Medium	Array, Binary Search, Dynamic Programming, Sliding Window, Rolling Hash, Hash Function
254	Maximum Number of Balloons	Easy	Hash Table, String, Counting
255	Maximum Number of Coins You Can Get	Medium	Array, Math, Greedy, Sorting, Game Theory
256	Maximum Performance of a Team	Hard	Array, Greedy, Sorting, Heap (Priority Queue)
257	Maximum Points You Can Obtain from Cards	Medium	Array, Sliding Window, Prefix Sum
258	Maximum Population Year	Easy	Array, Counting, Prefix Sum
259	Maximum Product of Splitted Binary Tree	Medium	Tree, Depth-First Search, Binary Tree
260	Maximum Product of Three Numbers	Easy	Array, Math, Sorting
261	Maximum Product of Two Elements in an Array	Easy	Array, Sorting, Heap (Priority Queue)
262	Maximum Product of Word Lengths	Medium	Array, String, Bit Manipulation
263	Maximum Product Subarray	Medium	Array, Dynamic Programming
264	Maximum Profit in Job Scheduling	Hard	Array, Binary Search, Dynamic Programming, Sorting
265	Maximum Score from Performing Multiplication Operations	Hard	Array, Dynamic Programming
266	Maximum Score of a Good Subarray	Hard	Array, Two Pointers, Binary Search, Stack, Monotonic Stack, Cartesian Tree
267	Maximum Split of Positive Even Integers	Medium	Math, Backtracking, Greedy
268	Maximum Subarray	Medium	Array, Divide and Conquer, Dynamic Programming
269	Maximum Sum Circular Subarray	Medium	Array, Divide and Conquer, Dynamic Programming, Queue, Monotonic Queue
270	Maximum Sum of Distinct Subarrays With Length K	Medium	Array, Hash Table, Sliding Window
271	Maximum Units on a Truck	Easy	Array, Greedy, Sorting
272	Maximum Width of Binary Tree	Medium	Tree, Depth-First Search, Breadth-First Search, Binary Tree
273	Maximum XOR of Two Numbers in an Array	Medium	Array, Hash Table, Bit Manipulation, Trie
274	Median of Two Sorted Arrays	Hard	Array, Binary Search, Divide and Conquer
275	Merge Intervals	Medium	Array, Sorting, Quicksort
276	Merge k Sorted Lists	Hard	Linked List, Divide and Conquer, Heap (Priority Queue), Merge Sort, Tournament Sort
277	Merge Sorted Array	Easy	Array, Two Pointers, Sorting
278	Merge Two Sorted Lists	Easy	Linked List, Recursion
279	Min Cost Climbing Stairs	Easy	Array, Dynamic Programming
280	Min Cost to Connect All Points	Medium	Array, Union-Find, Graph Theory, Minimum Spanning Tree, Prim's Algorithm, Kruskal's Algorithm, Borůvka's Algorithm
281	Min Stack	Medium	Stack, Design
282	Mini Parser	Medium	String, Stack, Depth-First Search
283	Minimize Deviation in Array	Hard	Array, Greedy, Heap (Priority Queue), Ordered Set
284	Minimize Maximum Pair Sum in Array	Medium	Array, Two Pointers, Greedy, Sorting
285	Minimum Absolute Difference	Easy	Array, Sorting
286	Minimum Absolute Difference in BST	Easy	Tree, Depth-First Search, Breadth-First Search, Binary Search Tree, Binary Tree
287	Minimum Add to Make Parentheses Valid	Medium	String, Stack, Greedy, Bracket Sequences
288	Minimum Amount of Time to Collect Garbage	Medium	Array, String, Prefix Sum
289	Minimum Cost For Tickets	Medium	Array, Dynamic Programming
290	Minimum Cost Homecoming of a Robot in a Grid	Medium	Array, Greedy
291	Minimum Cost to Cut a Stick	Hard	Array, Dynamic Programming, Sorting
292	Minimum Difficulty of a Job Schedule	Hard	Array, Dynamic Programming
293	Minimum Domino Rotations For Equal Row	Medium	Array, Greedy
294	Minimum Falling Path Sum	Medium	Array, Dynamic Programming, Matrix
295	Minimum Height Trees	Medium	Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
296	Minimum Insertion Steps to Make a String Palindrome	Hard	String, Dynamic Programming
297	Minimum Limit of Balls in a Bag	Medium	Array, Binary Search
298	Minimum Moves to Equal Array Elements II	Medium	Array, Math, Sorting
299	Minimum Moves to Spread Stones Over Grid	Medium	Array, Dynamic Programming, Backtracking, Bit Manipulation, Matrix, Bitmask
300	Minimum Number of Frogs Croaking	Medium	String, Counting
301	Minimum Number of Operations to Make Array Continuous	Hard	Array, Hash Table, Binary Search, Sliding Window
302	Minimum Number of Refueling Stops	Hard	Array, Dynamic Programming, Greedy, Heap (Priority Queue)
303	Minimum Number of Steps to Make Two Strings Anagram	Medium	Hash Table, String, Counting
304	Minimum Number of Taps to Open to Water a Garden	Hard	Array, Dynamic Programming, Greedy
305	Minimum Operations to Make the Array Alternating	Medium	Array, Hash Table, Greedy, Counting
306	Minimum Operations to Reduce X to Zero	Medium	Array, Hash Table, Binary Search, Sliding Window, Prefix Sum
307	Minimum Path Cost in a Grid	Medium	Array, Dynamic Programming, Matrix
308	Minimum Path Sum	Medium	Array, Dynamic Programming, Matrix
309	Minimum Remove to Make Valid Parentheses	Medium	String, Stack
310	Minimum Size Subarray Sum	Medium	Array, Binary Search, Sliding Window, Prefix Sum
311	Minimum Swaps To Make Sequences Increasing	Hard	Array, Dynamic Programming
312	Minimum Time to Make Rope Colorful	Medium	Array, String, Dynamic Programming, Greedy
313	Minimum Window Substring	Hard	Hash Table, String, Sliding Window
314	Missing Number	Easy	Array, Hash Table, Math, Binary Search, Bit Manipulation, Sorting
315	Most Stones Removed with Same Row or Column	Medium	Hash Table, Depth-First Search, Union-Find, Graph Theory, Bipartite Graph
316	Move Zeroes	Easy	Array, Two Pointers
317	Moving Average from Data Stream	Easy	Array, Design, Queue, Data Stream
318	My Calendar I	Medium	Array, Binary Search, Design, Segment Tree, Ordered Set
319	N-ary Tree Level Order Traversal	Medium	Tree, Breadth-First Search
320	N-Queens	Hard	Array, Backtracking, Algorithm X
321	N-Queens II	Hard	Backtracking, Algorithm X
322	N-th Tribonacci Number	Easy	Math, Dynamic Programming, Memoization
323	Network Delay Time	Medium	Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Shortest Path, Dijkstra's Algorithm
324	Next Greater Element I	Easy	Array, Hash Table, Stack, Monotonic Stack
325	Next Greater Element II	Medium	Array, Stack, Monotonic Stack
326	Next Greater Element III	Medium	Math, Two Pointers, String
327	Next Permutation	Medium	Array, Two Pointers
328	Non-decreasing Array	Medium	Array
329	Non-negative Integers without Consecutive Ones	Hard	Dynamic Programming
330	Non-overlapping Intervals	Medium	Array, Dynamic Programming, Greedy, Sorting
331	Number of Dice Rolls With Target Sum	Medium	Dynamic Programming
332	Number of Islands	Medium	Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
333	Number of Matching Subsequences	Medium	Array, Hash Table, String, Binary Search, Dynamic Programming, Trie, Sorting
334	Number of Provinces	Medium	Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
335	Number of Subarrays with Bounded Maximum	Medium	Array, Two Pointers
336	Number of Submatrices That Sum to Target	Hard	Array, Hash Table, Matrix, Prefix Sum
337	Number of Ways to Divide a Long Corridor	Hard	Math, String, Dynamic Programming
338	Numbers At Most N Given Digit Set	Hard	Array, Math, String, Binary Search, Dynamic Programming
339	Odd Even Linked List	Medium	Linked List
340	Ones and Zeroes	Medium	Array, String, Dynamic Programming, Knapsack Problem, 0-1 Knapsack
341	Online Stock Span	Medium	Stack, Design, Monotonic Stack, Data Stream
342	Orderly Queue	Hard	Math, String, Sorting, Lexicographically Minimal String Rotation
343	Out of Boundary Paths	Medium	Dynamic Programming
344	Paint House III	Hard	Array, Dynamic Programming
345	Pairs of Songs With Total Durations Divisible by 60	Medium	Array, Hash Table, Counting
346	Palindrome Linked List	Easy	Linked List, Two Pointers, Stack, Recursion
347	Palindrome Pairs	Hard	Array, Hash Table, String, Trie, Hash Function
348	Palindrome Partitioning	Medium	String, Dynamic Programming, Backtracking
349	Palindrome Partitioning II	Hard	String, Dynamic Programming
350	Palindromic Substrings	Medium	Two Pointers, String, Dynamic Programming
351	Partition Array into Disjoint Intervals	Medium	Array
352	Partition Labels	Medium	Hash Table, Two Pointers, String, Greedy
353	Partition to K Equal Sum Subsets	Medium	Array, Dynamic Programming, Backtracking, Bit Manipulation, Memoization, Bitmask
354	Partitioning Into Minimum Number Of Deci-Binary Numbers	Medium	String, Greedy
355	Pascal's Triangle	Easy	Array, Dynamic Programming
356	Path Sum II	Medium	Backtracking, Tree, Depth-First Search, Binary Tree
357	Path Sum III	Medium	Tree, Depth-First Search, Binary Tree
358	Path with Maximum Probability	Medium	Array, Graph Theory, Heap (Priority Queue), Shortest Path, Dijkstra's Algorithm
359	Path With Minimum Effort	Medium	Array, Binary Search, Depth-First Search, Breadth-First Search, Union-Find, Heap (Priority Queue), Matrix, Dijkstra's Algorithm
360	Peak Index in a Mountain Array	Medium	Array, Binary Search, Ternary Search
361	Peeking Iterator	Medium	Array, Design, Iterator
362	Perfect Number	Easy	Math
363	Perfect Squares	Medium	Math, Dynamic Programming, Breadth-First Search, Knapsack Problem, Complete Knapsack
364	Permutation in String	Medium	Hash Table, Two Pointers, String, Sliding Window
365	Plus One	Easy	Array, Math
366	Populating Next Right Pointers in Each Node	Medium	Linked List, Tree, Depth-First Search, Breadth-First Search, Binary Tree
367	Populating Next Right Pointers in Each Node	Medium	Linked List, Tree, Depth-First Search, Breadth-First Search, Binary Tree
368	Pow(x, n)	Medium	Math, Recursion
369	Prefix and Suffix Search	Hard	Array, Hash Table, String, Design, Trie
370	Product of Array Except Self	Medium	Array, Prefix Sum
371	Product of the Last K Numbers	Medium	Array, Math, Design, Data Stream, Prefix Sum
372	Pseudo-Palindromic Paths in a Binary Tree	Medium	Bit Manipulation, Tree, Depth-First Search, Breadth-First Search, Binary Tree
373	Push Dominoes	Medium	Two Pointers, String, Dynamic Programming
374	Random Pick with Weight	Medium	Array, Math, Binary Search, Prefix Sum, Randomized
375	Range Addition II	Easy	Array, Math
376	Range Sum Query - Mutable	Medium	Array, Divide and Conquer, Design, Binary Indexed Tree, Segment Tree, Sqrt Decomposition
377	Range Sum Query 2D - Immutable	Medium	Array, Design, Matrix, Prefix Sum
378	Reachable Nodes In Subdivided Graph	Hard	Graph Theory, Heap (Priority Queue), Shortest Path, Dijkstra's Algorithm
379	Reconstruct Itinerary	Hard	Array, String, Depth-First Search, Graph Theory, Sorting, Heap (Priority Queue), Eulerian Circuit, Eulerian Path, Semi-Eulerian Graph
380	Reconstruct Original Digits from English	Medium	Hash Table, Math, String
381	Recover Binary Search Tree	Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree
382	Reduce Array Size to The Half	Medium	Array, Hash Table, Greedy, Sorting, Heap (Priority Queue)
383	Reduction Operations to Make the Array Elements Equal	Medium	Array, Sorting
384	Redundant Connection	Medium	Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
385	Regions Cut By Slashes	Medium	Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Matrix, Planar Graph
386	Regular Expression Matching	Hard	String, Dynamic Programming, Recursion
387	Remove All Adjacent Duplicates In String	Easy	String, Stack
388	Remove All Adjacent Duplicates in String II	Medium	String, Stack
389	Remove Covered Intervals	Medium	Array, Sorting
390	Remove Duplicate Letters	Medium	String, Stack, Greedy, Monotonic Stack
391	Remove Duplicates from Sorted Array	Easy	Array, Two Pointers
392	Remove Duplicates from Sorted Array II	Medium	Array, Two Pointers
393	Remove Duplicates from Sorted List II	Medium	Linked List, Two Pointers
394	Remove Element	Easy	Array, Two Pointers
395	Remove Linked List Elements	Easy	Linked List, Recursion
396	Remove Nth Node From End of List	Medium	Linked List, Two Pointers
397	Remove Sub-Folders from the Filesystem	Medium	Array, String, Depth-First Search, Trie
398	Replace Elements with Greatest Element on Right Side	Easy	Array
399	Replace Words	Medium	Array, Hash Table, String, Trie
400	Reshape the Matrix	Easy	Array, Matrix, Simulation
401	Restore the Array From Adjacent Pairs	Medium	Array, Hash Table, Depth-First Search
402	Reverse Linked List	Easy	Linked List, Recursion
403	Reverse Linked List II	Medium	Linked List
404	Reverse Nodes in k-Group	Hard	Linked List, Recursion
405	Reverse Only Letters	Easy	Two Pointers, String
406	Reverse String II	Easy	Two Pointers, String
407	Reverse Words in a String	Medium	Two Pointers, String
408	Rotate Array	Medium	Array, Math, Two Pointers
409	Rotate Image	Medium	Array, Math, Matrix
410	Rotate List	Medium	Linked List, Two Pointers
411	Running Sum of 1d Array	Easy	Array, Prefix Sum
412	Russian Doll Envelopes	Hard	Array, Binary Search, Dynamic Programming, Sorting, Longest Increasing Subsequence
413	Satisfiability of Equality Equations	Medium	Array, String, Union-Find, Graph Theory
414	Score After Flipping Matrix	Medium	Array, Greedy, Bit Manipulation, Matrix
415	Score of Parentheses	Medium	String, Stack, Bracket Sequences
416	Search a 2D Matrix	Medium	Array, Binary Search, Matrix
417	Search a 2D Matrix II	Medium	Array, Binary Search, Divide and Conquer, Matrix
418	Search in Rotated Sorted Array	Medium	Array, Binary Search
419	Search in Rotated Sorted Array II	Medium	Array, Binary Search
420	Search Insert Position	Easy	Array, Binary Search
421	Search Suggestions System	Medium	Array, String, Binary Search, Trie, Sorting, Heap (Priority Queue)
422	Seat Reservation Manager	Medium	Design, Heap (Priority Queue)
423	Second Minimum Node In a Binary Tree	Easy	Tree, Depth-First Search, Binary Tree
424	Set Matrix Zeroes	Medium	Array, Hash Table, Matrix
425	Shifting Letters	Medium	Array, String, Prefix Sum
426	Shortest Path in a Grid with Obstacles Elimination	Hard	Array, Breadth-First Search, Matrix
427	Shortest Path in Binary Matrix	Medium	Array, Breadth-First Search, Matrix
428	Shortest Unsorted Continuous Subarray	Medium	Array, Two Pointers, Stack, Greedy, Sorting, Monotonic Stack
429	Shortest Way to Form String	Medium	Two Pointers, String, Binary Search, Greedy
430	Shuffle an Array	Medium	Array, Math, Design, Randomized
431	Simplify Path	Medium	String, Stack
432	Single Number	Easy	Array, Bit Manipulation
433	Single Number II	Medium	Array, Bit Manipulation
434	Single Number III	Medium	Array, Bit Manipulation
435	Sliding Window Maximum	Hard	Array, Queue, Sliding Window, Heap (Priority Queue), Monotonic Queue, Range Minimum/Maximum Query
436	Sliding Window Median	Hard	Array, Hash Table, Sliding Window, Heap (Priority Queue), Treap
437	Slowest Key	Easy	Array, String
438	Smallest Range I	Easy	Array, Math
439	Smallest String With A Given Numeric Value	Medium	String, Greedy
440	Smallest String With Swaps	Medium	Array, Hash Table, String, Depth-First Search, Breadth-First Search, Union-Find, Sorting
441	Smallest Subsequence of Distinct Characters	Medium	String, Stack, Greedy, Monotonic Stack
442	Smallest Subtree with all the Deepest Nodes	Medium	Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree, Binary Lifting, Lowest Common Ancestor, DP on Trees
443	Sort an Array	Medium	Array, Divide and Conquer, Sorting, Heap (Priority Queue), Merge Sort, Bucket Sort, Radix Sort, Counting Sort
444	Sort Array By Parity II	Easy	Array, Two Pointers, Sorting
445	Sort Colors	Medium	Array, Two Pointers, Sorting, Quicksort, Bubble Sort
446	Sort Vowels in a String	Medium	String, Sorting
447	Spiral Matrix	Medium	Array, Matrix, Simulation
448	Spiral Matrix II	Medium	Array, Matrix, Simulation
449	Split Array Largest Sum	Hard	Array, Binary Search, Dynamic Programming, Greedy, Prefix Sum
450	Split Linked List in Parts	Medium	Linked List
451	Sqrt(x)	Easy	Math, Binary Search, Newton's Method
452	Squares of a Sorted Array	Easy	Array, Two Pointers, Sorting
453	Steps to Make Array Non-decreasing	Medium	Array, Linked List, Dynamic Programming, Stack, Monotonic Stack, Simulation
454	Stock Price Fluctuation	Medium	Hash Table, Design, Heap (Priority Queue), Data Stream, Ordered Set
455	Stone Game	Medium	Array, Math, Dynamic Programming, Minimax, Game Theory, Zero-Sum Game
456	Stone Game IV	Hard	Math, Dynamic Programming, Minimax, Game Theory, Nim Game, Sprague–Grundy Theorem, Zero-Sum Game
457	Stone Game VII	Medium	Array, Math, Dynamic Programming, Minimax, Game Theory, Zero-Sum Game
458	Stream of Characters	Hard	Array, String, Design, Trie, Data Stream, Aho–Corasick Algorithm
459	Student Attendance Record I	Easy	String
460	Subarray Sum Equals K	Medium	Array, Hash Table, Prefix Sum
461	Subarrays with K Different Integers	Hard	Array, Hash Table, Sliding Window, Counting
462	Subsets	Medium	Array, Backtracking, Bit Manipulation
463	Subsets II	Medium	Array, Backtracking, Bit Manipulation
464	Subtree of Another Tree	Easy	Tree, Depth-First Search, String Matching, Binary Tree, Hash Function
465	Sudoku Solver	Hard	Array, Hash Table, Backtracking, Matrix, Algorithm X, Dancing Links
466	Sum of Absolute Differences in a Sorted Array	Medium	Array, Math, Prefix Sum
467	Sum of Beauty in the Array	Medium	Array
468	Sum of Distances in Tree	Hard	Dynamic Programming, Tree, Depth-First Search, Graph Theory, DP on Trees
469	Sum of Square Numbers	Medium	Math, Two Pointers, Binary Search
470	Sum of Subarray Minimums	Medium	Array, Dynamic Programming, Stack, Monotonic Stack
471	Super Palindromes	Hard	Math, String, Enumeration
472	Surrounded Regions	Medium	Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
473	Swap Nodes in Pairs	Medium	Linked List, Recursion
474	Symmetric Tree	Easy	Tree, Depth-First Search, Breadth-First Search, Binary Tree
475	Target Sum	Medium	Array, Dynamic Programming, Backtracking, Knapsack Problem, 0-1 Knapsack
476	Teemo Attacking	Easy	Array, Simulation
477	The Number of the Smallest Unoccupied Chair	Medium	Array, Hash Table, Heap (Priority Queue)
478	Third Maximum Number	Easy	Array, Sorting
479	Three Equal Parts	Hard	Array, Math
480	Time Based Key-Value Store	Medium	Hash Table, String, Binary Search, Design
481	To Lower Case	Easy	String
482	Top K Frequent Elements	Medium	Array, Hash Table, Divide and Conquer, Sorting, Heap (Priority Queue), Bucket Sort, Counting, Quickselect
483	Top K Frequent Words	Medium	Array, Hash Table, String, Trie, Sorting, Heap (Priority Queue), Bucket Sort, Counting
484	Trapping Rain Water	Hard	Array, Two Pointers, Dynamic Programming, Stack, Monotonic Stack
485	Triangle	Medium	Array, Dynamic Programming
486	Two City Scheduling	Medium	Array, Greedy, Sorting, Hungarian Algorithm, Successive Shortest Path Algorithm
487	Two Sum	Easy	Array, Hash Table
488	Two Sum II - Input Array Is Sorted	Medium	Array, Two Pointers, Binary Search
489	Two Sum IV - Input is a BST	Easy	Hash Table, Two Pointers, Tree, Depth-First Search, Breadth-First Search, Binary Search Tree, Binary Tree
490	Uncommon Words from Two Sentences	Easy	Hash Table, String, Counting
491	Unique Binary Search Trees	Medium	Math, Dynamic Programming, Tree, Binary Search Tree, Binary Tree
492	Unique Binary Search Trees II	Medium	Dynamic Programming, Backtracking, Tree, Binary Search Tree, Binary Tree
493	Unique Email Addresses	Easy	Array, Hash Table, String
494	Unique Length-3 Palindromic Subsequences	Medium	Hash Table, String, Bit Manipulation, Prefix Sum
495	Unique Paths	Medium	Math, Dynamic Programming, Combinatorics
496	Unique Paths II	Medium	Array, Dynamic Programming, Matrix
497	Unique Paths III	Hard	Array, Backtracking, Bit Manipulation, Matrix, Hamiltonian Path
498	Valid Mountain Array	Easy	Array
499	Valid Number	Hard	String
500	Valid Parentheses	Easy	String, Stack, Bracket Sequences
501	Valid Sudoku	Medium	Array, Hash Table, Matrix
502	Valid Tic-Tac-Toe State	Medium	Array, Matrix
503	Valid Triangle Number	Medium	Array, Two Pointers, Binary Search, Greedy, Sorting
504	Validate Binary Search Tree	Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree
505	Validate Stack Sequences	Medium	Array, Stack, Simulation
506	Vertical Order Traversal of a Binary Tree	Hard	Hash Table, Tree, Depth-First Search, Breadth-First Search, Sorting, Binary Tree
507	Word Break	Medium	Array, Hash Table, String, Dynamic Programming, Trie, Memoization, Brute-Force Search
508	Word Ladder	Hard	Hash Table, String, Breadth-First Search, Bidirectional Search
509	Word Ladder II	Hard	Hash Table, String, Backtracking, Breadth-First Search, Bidirectional Search
510	Word Search	Medium	Array, String, Backtracking, Depth-First Search, Matrix
511	Word Search II	Hard	Array, String, Backtracking, Trie, Matrix

Other Repository Problemset

#	Problem	Difficulty	Topics
1	Activity Selection problem	-	-
2	Adding Exits to a Maze	-	-
3	Backtracking N-Queens	-	-
4	Binary Insertion Sort	-	-
5	Car Fueling	-	-
6	Check brackets in the code	-	-
7	Check if a given sequence of moves for a robot is circular or not	-	-
8	Checking Consistency of CS Curriculum	-	-
9	Checking whether a Graph is Bipartite	-	-
10	Checking Whether Any Intersection in a City is Reachable from Any Other	-	-
11	Compute tree height	-	-
12	Computing the Minimum Number of Flight Segments	-	-
13	Convert a given Binary Tree to Doubly Linked List	-	-
14	Count Inversions in an array	-	-
15	Counting Sort - Segregation logic to Sort an array of 0's, 1's and 2's	-	-
16	Cycle Sort In Range 1 To N	-	-
17	Determining an Order of Courses	-	-
18	Device Application Pairs	-	-
19	Disjoint Set (Or Union-Find) | (Detect Cycle in an Undirected Graph)	-	-
20	Disjoint Set (Union By Rank and Path Compression Algorithm) | (Detect Cycle in an Undirected Graph)	-	-
21	Edit Distance II	-	-
22	Find All Permutations and Combinations of a List	-	-
23	Find All Permutations of a List	-	-
24	Find All Subsets of a List	-	-
25	Find All Subsets of a List of size k	-	-
26	Find Distance In A Binary Tree	-	-
27	Find Maximum Value in Array	-	-
28	Find minimum number of coins that make a given value	-	-
29	Find Number in Rotated Array	-	-
30	Find position of an element in a sorted array of infinite numbers	-	-
31	Find the First Non-Repeating Character in a Stream	-	-
32	Find the Rotation Count in Rotated Sorted array	-	-
33	Finding an Exit from Maze	-	-
34	First Negative In Every Window	-	-
35	Flip	-	-
36	Implement K Queues in a Single Array	-	-
37	Insertion Sort	-	-
38	Interleave The First Half Of The Queue With The Second Half	-	-
39	Job Sequencing Problem	-	-
40	k largest(or smallest) elements in an array	-	-
41	Keyboard Rows	-	-
42	Knuth Moris Pratt - Pattern Searching Algorithm	-	-
43	Kruskal’s Minimum Spanning Tree Algorithm	-	-
44	Left Side Less Right Side More	-	-
45	Lexicographically smallest string formed by appending a character from the first K characters of a given string	-	-
46	Lexicographically smallest string formed by removing at most one character	-	-
47	Longest Common Subsequence of Three Sequences	-	-
48	Longest Common Subsequence of Two Sequences	-	-
49	Max Distance	-	-
50	Maximum Amount of Gold	-	-
51	Maximum Unsorted Subarray	-	-
52	Merge Sort	-	-
53	Minimum Number of Platforms Required for a Railway Station	-	-
54	Minimum number of swaps required to sort an array	-	-
55	Money Change	-	-
56	Move All Zeros To End Of List	-	-
57	N Stacks In An Array	-	-
58	N-Knights	-	-
59	Network packet processing simulation	-	-
60	Nth Fibonacci Number Modulo M	-	-
61	Partitioning Souvenirs	-	-
62	Primitive Calculator	-	-
63	Pythagorean Triplet In An Array	-	-
64	Quick Sort	-	-
65	Rabin-Karp Algorithm For Pattern Matching/Searching	-	-
66	Radix Sort	-	-
67	Rectangle Overlap problem	-	-
68	Reverse First K elements of Queue	-	-
69	Rotate A Matrix By 90 Degree	-	-
70	Segment Tree	-	-
71	Shortest Path in Directed Acyclic Graph	-	-
72	Sort A Stack	-	-
73	Sorted Permutation Rank	-	-
74	Sorting	-	-
75	Subarrays with distinct elements	-	-
76	Submatrix Sum Queries	-	-
77	Subset Sum	-	-
78	Sum of minimum and maximum elements of all subarrays of size “K”	-	-
79	Super Ugly Numbers	-	-
80	Tree	-	-
81	Ugly Numbers	-	-
82	Unbounded Knapsack (Repetition of items allowed)	-	-
83	Valid Ip Addresses	-	-
84	Water Overflow	-	-
85	Word Break Map Problem	-	-
86	Word Break Problem	-	-

Automation

Use tools/leetcode_agent.py to scaffold a new solved problem from a LeetCode URL. Step 1 creates the problem folder inside problems/ with fetched README.md and empty solution.py; step 2 updates this index, commits, and pushes.