Coding challenges from www.leetcode.com

Tree

ID	Name	Rating	Note
144	Binary Tree Preorder Traversal	Alpha
94	Binary Tree Inorder Traversal	Alpha
145	Binary Tree Postorder Traversal	Alpha
429	N-ary Tree Level Order Traversal	Alpha+
589	N-ary Tree Preorder Traversal	Alpha
590	N-ary Tree Postorder Traversal	Alpha
100	Same Tree	Alpha+
572	Subtree of Another Tree	Alpha+
101	Symmetric Tree	Alpha+
965	Univalued Binary Tree	Alpha+
226	Invert Binary Tree	Alpha	postorder
112	Path Sum	Alpha+
113	Path Sum II	Alpha+
437	Path Sum III	Alpha+	preorder
124	Binary Tree Maximum Path Sum	Alpha+	postorder
543	Diameter of Binary Tree	Alpha+	postorder
N14	Diameter of Generic Tree	Alpha	I.Q.
687	Longest Univalue Path	Alpha+	postorder
250	Count Univalue Subtrees	Alpha+	postorder
104	Maximum Depth of Binary Tree	Alpha+	postorder
366	Find Leaves of Binary Tree	Alpha+	postorder
111	Minimum Depth of Binary Tree	Alpha+	postorder, BFS
257	Binary Tree Paths	Alpha+
129	Sum Root to Leaf Numbers	Alpha+
298	Binary Tree Longest Consecutive Sequence	Alpha+
549	Binary Tree Longest Consecutive Sequence II	Alpha+
110	Balanced Binary Tree	Alpha+
102	Binary Tree Level Order Traversal	Alpha+	postorder, BFS
107	Binary Tree Level Order Traversal II	Alpha	postorder, BFS
314	Binary Tree Vertical Order Traversal	Alpha+	BFS
103	Binary Tree Zigzag Level Order Traversal	Alpha	BFS
199	Binary Tree Right Side View	Alpha+	preorder
114	Flatten Binary Tree to Linked List	Alpha+	preorder
222	Count Complete Tree Nodes	Alpha+
105	Construct Binary Tree from Preorder and Inorder Traversal	Alpha+	preorder
106	Construct Binary Tree from Inorder and Postorder Traversal	Alpha+	postorder
331	Verify Preorder Serialization of a Binary Tree	Charlie
116	Populating Next Right Pointers in Each Node	Alpha	BFS, preorder
117	Populating Next Right Pointers in Each Node II	Alpha	BFS, preorder
297	Serialize and Deserialize Binary Tree	Alpha+	preorder
428	Serialize and Deserialize N-ary Tree	Alpha+	preorder
449	Serialize and Deserialize Binary Search Tree	Alpha
236	Lowest Common Ancestor of a Binary Tree	Alpha+	mechanical, postorder
1676	Lowest Common Ancestor of a Binary Tree IV	Alpha+	postorder
1644	Lowest Common Ancestor of a Binary Tree II	Alpha+	postorder
1650	Lowest Common Ancestor of a Binary Tree III	Alpha+
235	Lowest Common Ancestor of a Binary Search Tree	Alpha+
341	Flatten Nested List Iterator	Bravo
339	Nested List Weight Sum	Alpha+	preorder
364	Nested List Weight Sum II	Alpha+	preorder
987	Vertical Order Traversal of a Binary Tree	Alpha+
1302	Deepest Leaves Sum	Alpha+
872	Leaf-Similar Trees	Alpha+
814	Binary Tree Pruning	Alpha+	postorder
1325	Delete Leaves With a Given Value	Alpha+	postorder
508	Most Frequent Subtree Sum	Alpha+	postorder
1973	Count Nodes Equal to Sum of Descendants	Alpha+	postorder
1120	Maximum Average Subtree	Alpha+	postorder
968	Binary Tree Cameras	Alpha	postorder
337	House Robber III	Alpha+	postorder
979	Distribute Coins in Binary Tree	Bravo	postorder

Binary Search Tree

ID	Name	Rating	Note
98	Validate Binary Search Tree	Alpha+	preorder, inorder, postorder
530	Minimum Absolute Difference in BST	Alpha+	inorder
700	Search in a Binary Search Tree	Alpha+	preorder
701	Insert into a Binary Search Tree	Alpha+	preorder
450	Delete Node in a BST	Alpha+	preorder
333	Largest BST Subtree	Alpha+	preorder
99	Recover Binary Search Tree	Alpha	Inorder
108	Convert Sorted Array to Binary Search Tree	Alpha+
109	Convert Sorted List to Binary Search Tree	Alpha+
173	Binary Search Tree Iterator	Bravo	mechanical
230	Kth Smallest Element in a BST	Alpha+
285	Inorder Successor in BST	Alpha+
270	Closest Binary Search Tree Value	Alpha+
272	Closest Binary Search Tree Value II	Alpha+
255	Verify Preorder Sequence in Binary Search Tree	Hard
96	Unique Binary Search Trees	Bravo
95	Unique Binary Search Trees II	Bravo
501	Find Mode in Binary Search Tree	Bravo
669	Trim a Binary Search Tree	Alpha+

Linked List

ID	Name	Rating	Note
141	Linked List Cycle	Alpha+
142	Linked List Cycle II	Alpha
876	Middle of the Linked List	Alpha+
234	Palindrome Linked List	Alpha+
24	Swap Nodes in Pairs	Alpha+
237	Delete Node in a Linked List	Alpha+
19	Remove Nth Node From End of List	Alpha+
1474	Delete N Nodes After M Nodes of a Linked List	Alpha
203	Remove Linked List Elements	Alpha+
1836	Remove Duplicates From an Unsorted Linked List	Alpha+
83	Remove Duplicates from Sorted List	Alpha+
82	Remove Duplicates from Sorted List II	Bravo
2	Add Two Numbers	Alpha+
445	Add Two Numbers II	Alpha+
369	Plus One Linked List	Alpha+
160	Intersection of Two Linked Lists	Alpha+
21	Merge Two Sorted Lists	Alpha+
143	Reorder List	Alpha
147	Insertion Sort List	Alpha	insertion sort
148	Sort List	Alpha+	merge sort
61	Rotate List	Alpha+
86	Partition List	Alpha+
23	Merge k Sorted Lists	Alpha+
206	Reverse Linked List	Alpha+
92	Reverse Linked List II	Alpha
25	Reverse Nodes in k-Group	Alpha
707	Designed Linked List	Bravo
1290	Convert Binary Number in a Linked List to Integer	Alpha

Graph

ID	Name	Rating	Note
N1	Minimum Distance Between Two Points in a Matrix	Alpha+	BFS
N2	Shortest Path Between Two Points in a Matrix	Alpha+	BFS
N3	Unique Paths from Top Left to Bottom Right	Alpha+	BFS
127	Word Ladder	Alpha+	BFS
126	Word Ladder II	Hard, BFS
752	Open the Lock	Alpha+	BFS
542	01 Matrix	Alpha+	BFS
286	Walls and Gates	Alpha+	BFS
934	Shortest Bridge	Alpha+	BFS
433	Minimum Genetic Mutation	Alpha+	BFS
815	Bus Routes	Alpha+	BFS
111	Minimum Depth of Binary Tree	Alpha+	postorder, BFS
773	Sliding Puzzle	Alpha+
863	All Nodes Distance K in Binary Tree	Alpha+	BFS
1129	Shortest Path with Alternating Colors	Alpha+	BFS, mechanical
847	Shortest Path Visiting All Nodes	Alpha	multidimensional BFS
864	Shortest Path to Get All Keys	Alpha+	multidimensional BFS
207	Course Schedule	Alpha+	topological sort
N15	Construct Dependency Graph	Alpha+	I.Q., graph traversal, postorder
210	Course Schedule II	Alpha+	topological sort, postorder
802	Find Eventual Safe States	Alpha+	topological sort
785	Is Graph Bipartite	Alpha+	bipartition, coloring
886	Possible Bipartition	Alpha+	bipartition, coloring
1042	Flower Planting With No Adjacent	Alpha+	coloring, greedy
133	Clone Graph	Alpha+	clone
1490	Clone N-ary Tree	Alpha	clone
138	Copy List with Random Pointer	Alpha	clone
1485	Clone Binary Tree With Random Pointer	Alpha	clone
797	All Paths From Source to Target	Alpha+	graph traversal
399	Evaluate Division	Alpha+	graph traversal
N5	Union Find	Alpha+	union find
990	Satisfiability of Equality Equations	Alpha+	union find
261	Graph Valid Tree	Alpha+	union find
305	Number of Islands II	Alpha+	union find
323	Number of Connected Components in an Undirected Graph	Alpha+	union find
547	Number of Provinces	Alpha+	union find
684	Redundant Connection	Alpha+	union find
721	Accounts Merge	Bravo	union find
200	Number of Islands	Alpha+	DFS, union find
733	Flood Fill	Alpha+	DFS
1905	Count Sub Islands	Alpha+	DFS
695	Max Area of Island	Alpha+	DFS, union find
694	Number of Distinct Islands	Alpha+	DFS
463	Island Perimeter	Alpha
827	Making a Large Island	Alpha+	DFS, union find
1162	As Far from Land as Possible	Alpha+	BFS
130	Surrounded Regions	Alpha
841	Keys and Rooms	Alpha+	DFS
1202	Smallest String With Swaps	Alpha	union find
839	Similar String Groups	Alpha	union find
952	Largest Component Size by Common Factor	Alpha+	union find
737	Sentence Similarity II	Alpha+	union find
1319	Number of Operations to Make Network Connected	Alpha+	union find
959	Regions Cut By Slashes	Alpha+	union find
997	Find the Town Judge	Alpha+
N6	Dijkstra	Alpha+	Dijkstra
743	Network Delay Time	Alpha+	Dijkstra
787	Cheapest Flights Within K Stops	Alpha+	Dijkstra
1631	Path With Minimum Effort	Alpha	Dijkstra
1514	Path with Maximum Probability	Alpha	Dijkstra
1334	Find the City With the Smallest Number of Neighbors at a Threshold Distance	Alpha	Dijkstra
332	Reconstruct Itinerary	Charlie
79	Word Search	Alpha+
212	Word Search II	Alpha	Trie, DFS
329	Longest Increasing Path in a Matrix	Alpha+	DFS
489	Robot Room Cleaner	Alpha+
N11	Shortest Path Given Robot API	Alpha+

Sliding window

ID	Name	Rating	Note
239	Sliding Window Maximum	Alpha+	sliding window, monotonic queue
209	Minimum Size Subarray Sum	Alpha+
567	Permutation in String	Alpha+
438	Find All Anagrams in a String	Alpha+
76	Minimum Window Substring	Alpha+
1438	Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit	Alpha+
217	Contains Duplicate	Alpha+
219	Contains Duplicate II	Alpha+
220	Contains Duplicate III	Alpha+
3	Longest Substring Without Repeating Characters	Alpha+
1695	Maximum Erasure Value	Alpha+
159	Longest Substring with At Most Two Distinct Characters	Alpha+
340	Longest Substring with At Most K Distinct Characters	Alpha+
424	Longest Repeating Character Replacement	Alpha
395	Longest Substring with At Least K Repeating Characters	Alpha+
2067	Number of Equal Count Substrings	Alpha
992	Subarrays with K Different Integers	Alpha+
1004	Max Consecutive Ones III	Alpha+
487	Max Consecutive Ones II	Alpha+
1052	Grumpy Bookstore Ownder	Alpha
1100	Find K-Length Substrings With No Repeated Characters	Alpha+
1151	Minimum Swaps to Group All 1's Together	Alpha+
1208	Get Equal Substrings Within Budget	Alpha+
1423	Maximum Points You Can Obtain from Cards	Alpha+
1176	Diet Plan Performance	Alpha
1456	Maximum Number of Vowels in a Substring of Given Length	Alpha+
1658	Minimum Operations to Reduce X to Zero	Alpha+

Binary Search

ID	Name	Rating	Note
35	Search Insert Position	Alpha+
704	Binary Search	Alpha+
1150	Check If a Number Is Majority Element in a Sorted Array	Alpha+
475	Heaters	Alpha
441	Arranging Coins	Alpha+
367	Valid Perfect Square	Alpha+
69	Sqrt(x)	Alpha+
611	Valid Triangle Number	Alpha+
33	Search in Rotated Sorted Array	Alpha+
81	Search in Rotated Sorted Array II	Alpha+
153	Find Minimum in Rotated Sorted Array	Alpha+	Devide and Conquer
154	Find Minimum in Rotated Sorted Array II	Alpha+
34	Find First and Last Position of Element in Sorted Array	Alpha+
315	Count of Smaller Numbers After Self	Alpha+
378	Kth Smallest Element in a Sorted Matrix	Alpha+	binary search, priority queue
668	Kth Smallest Number in Multiplication Table	Alpha
719	Find K-th Smallest Pair Distance	Alpha
74	Search a 2D Matrix	Alpha+
240	Search a 2D Matrix II	Alpha, Mechanical
287	Find the Duplicate Number	Bravo
162	Find Peak Element	Bravo
852	Peack Index in a Mountain Array	Alpha+
1095	Find in Mountain Array	Alpha
4	Median of Two Sorted Arrays	Alpha	mechanical
274	H-Index	Alpha	See 275
275	H-Index II	Alpha
278	First Bad Version	Alpha+
875	Koko Eating Bananas	Alpha+	koko-eat-bananas
1011	Capacity To Ship Packages Within D Days	Alpha+	koko-eat-bananas
1891	Cutting Ribbons	Alpha+	koko-eat-bananas
981	Time Based Key-Value Store	Alpha+
215	Kth Largest Element in an Array	Alpha	quick sort, binary search

Two Pointers

ID	Name	Rating	Note
455	Assign Cookies	Alpha	two pointers
125	Valid Palindrome	Alpha+	two pointers
917	Reverse Only Letters	Alpha+	two pointers
42	Trapping Rain Water	Alpha+	dynamic programming, two pointers, monotonic stack
11	Container With Most Water	Alpha+	two pointers
1498	Number of Subsequences That Satisfy the Given Sum Condition	Bravo	two pointers
925	Long Pressed Name	Bravo
986	Interval List Intersection	Alpha+	two pointers, intervals
881	Boats to Save People	Alpha+
977	Squares of a Sorted Array	Alpha+

Backtracking

ID	Name	Rating	Note
46	Permutations	Alpha+
47	Permutations II	Alpha+
996	Number of Squareful Arrays	Alpha+
77	Combinations	Alpha+
78	Subsets	Alpha+
491	Increasing Subsequence	Alpha+
39	Combination Sum	Alpha+
40	Combination Sum II	Alpha+
90	Subsets II	Alpha+
216	Combination Sum III	Alpha+
377	Combination Sum IV	Charlie
254	Factor Combinations	Alpha+
17	Letter Combinations of a Phone Number	Alpha+
51	N-Queens	Alpha+
52	N-Queens II	Alpha+	See 51 N-Queens
37	Sudoku Solver	Alpha+
22	Generate Parentheses	Alpha+
241	Different Ways to Add Parentheses	Alpha+
139	Word Break	Alpha+	DFS, dynamic programming
140	Word Break II	Alpha
267	Palindrome Permutation II	Alpha+
784	Letter Case Permutation	Alpha+	DFS
698	Partition to K Equal Sum Subsets	Alpha+
93	Restore IP Addresses	Alpha+
842	Split Array into Fibonacci Sequence	Alpha+
131	Palindrome Partitioning	Alpha+
282	Expression Add Operators	Alpha

Two Sum Series

ID	Name	Rating	Note
1	Two Sum	Alpha+
170	Two Sum III - Data structure design	Alpha+
653	Two Sum IV - Input is a BST	Alpha
167	Two Sum II - Input array is sorted	Alpha+	Two pointers
1099	Two Sum Less Than K	Alpha+	Two pointers
18	4Sum	Alpha+	Two pointers
15	3Sum	Alpha	Two pointers
16	3Sum Closest	Alpha	Two pointers
259	3Sum Smaller	Alpha	Two pointers
454	4Sum II	Alpha+	hash table

Parentheses Series

ID	Name	Rating	Note
20	Valid Parentheses	Alpha
32	Longest Valid Parentheses	Charlie
22	Generate Parentheses	Alpha+
301	Remove Invalid Parentheses	Alpha+
241	Different Ways to Add Parentheses	Alpha+
856	Score of Parentheses	Exotic
921	Minimum Add to Make Parentheses Valid	Bravo
1249	Minimum Remove to Make Valid Parentheses	Alpha
1190	Reverse Substrings Between Each Pair of Parentheses	Bravo, Mechanical

Prefix Sum

ID	Name	Rating	Note
325	Maximum Size Subarray Sum Equals k	Alpha+	prefix sum
525	Contiguous Array	Alpha+
862	Shortest Subarray with Sum at Least K	Hard	running sum, mechanical
560	Subarray Sum Equals K	Alpha+	prefix sum, hash map
930	Binary Subarrays With Sum	Alpha	prefix sum, hash map
1074	Number of Submatriecs That Sum To Target	TODO
N16	Find Minimum Length of Two Non-Overlapping Subarrays Each with a Sum Equal to Target	I.Q.

Stack, Queue & Priority Queue

ID	Name	Rating	Note
155	Min Stack	Alpha+
232	Implement Queue using Stacks	Bravo
225	Implement Stack using Queues	Bravo
150	Evaluate Reverse Polish Notation	Alpha+
42	Trapping Rain Water	Alpha+	dynamic programming, two pointers, monotonic stack
84	Largest Rectangle in Histogram	Alpha+	monotonic stack
503	Next Greater Element II	Alpha+	monotonic stack
739	Daily Temperatures	Alpha+	monotonic stack
496	Next Greater Element I	Alpha	monotonic stack
239	Sliding Window Maximum	Alpha+	sliding window, monotonic queue
901	Online Stock Span	Alpha	monotonic stack
347	Top K Frequent Elements	Alpha+
692	Top K Frequent Words	Alpha+
451	Sort Characters By Frequency	Alpha
295	Find Median from Data Stream	Alpha+
480	Sliding Window Median	Alpha+
373	Find K Pairs with Smallest Sums	Alpha+
218	The Skyline Problem	Bravo
973	K CLosest Points to Origin	Alpha+	priority queue, custom sort

Design

ID	Name	Rating	Note
359	Logger Rate Limiter	Alpha+
346	Moving Average from Data Stream	Alpha+
362	Design Hit Counter	Alpha+
281	Zigzag Iterator	Alpha
251	Flatten 2D Vector	Alpha
348	Design Tic-Tac-Toe	Bravo
146	LRU Cache	Alpha+
460	LFU Cache	Alpha
303	Range Sum Query - Immutable	Alpha
304	Range Sum Query 2D - Immutable	Alpha
N7	Timedelta Statistics	Alpha
N8	Endpoint Metrics	Alpha	I.Q.
N10	Dictionary Supports getRandom	Alpha	I.Q.

Trie

ID	Name	Rating	Note
208	Implement Trie (Prefix Tree)	Alpha+
212	Word Search II	Alpha+
648	Replace Words	Bravo
677	Map Sum Pairs	Alpha
211	Design Add and Search Words Data Structure	Alpha

Array

ID	Name	Rating	Note
27	Remove Element	Alpha+
283	Move Zeroes	Alpha+
26	Remove Duplicates from Sorted Array	Alpha+
80	Remove Duplicates from Sorted Array II	Alpha+
277	Find the Celebrity	Bravo
189	Rotate Array	Alpha+
299	Bulls and Cows	Bravo
134	Gas Station	Bravo
118	Pascal's Triangle	Alpha
119	Pascal's Triangle II	Charlie	Duplicate with 118
169	Majority Element	Alpha+
229	Majority Element II	Bravo
243	Shortest Word Distance	Alpha+
245	Shortest Word Distance III	Alpha
244	Shortest Word Distance II	Alpha
55	Jump Game	Alpha
45	Jump Game II	Alpha
128	Longest Consecutive Sequence	Alpha+
674	Longest Continuous Increasing Subsequence	Alpha+	dynamic programming
673	Number of Increasing Subsequence	Bravo	dynamic programming
164	Maximum Gap Bucket	Hard
135	Candy	Alpha
330	Patching Array	Hard
321	Create Maximum Number	Hard
56	Merge Intervals	Alpha+	intervals
57	Insert Intervals	Alpha+	intervals
252	Meeting Rooms	Alpha+
253	Meeting Rooms II	Alpha+
435	Non-overlapping Intervals	Alpha+	greedy
452	Minimum Number of Arrows to Burst Balloons	Alpha	greedy
1640	Check Array Formation Through Concatenation	Bravo
238	Product of Array Except Self	Alpha
228	Summary Ranges	Exotic
163	Missing Ranges	Exotic
88	Merge Sorted Array	Alpha
75	Sort Colors	Bravo	Two pointers, mechanical
41	First Missing Positive	Alpha	Two pointers
280	Wiggle Sort	Charlie
324	Wiggle Sort II	Charlie
370	Range Addition	Charlie
349	Intersection of Two Arrays	Alpha
350	Intersection of Two Arrays II	Alpha+
N17	Find the First, Second and Third Minimum Elements in an Array	Alpha+
334	Increasing Triplet Subsequence	Alpha	dynamic programming
414	Third Maximum Number	Alpha+
406	Queue Reconstruction by Height	Bravo, Mechanical
363	Max Sum of Rectangle No Larger Than K	Bravo	Mechanical
485	Max Consecutive Ones	Alpha+
849	Maximize Distance to Closest Person	Bravo
855	Exam Room	Bravo
645	Set Mismatch	Alpha+
912	Sort an Array	Bravo
1395	Count Number of Teams	Alpha

String

ID	Name	Rating	Note
28	Implement strStr()	Bravo
14	Longest Common Prefix	Alpha+
58	Length of Last Word	Alpha
344	Reverse String	Alpha+
186	Reverse Words in a String II	Alpha+
151	Reverse Words in a String	Alpha+
345	Reverse Vowels of a String	Alpha+
434	Number of Segments in a String	Alpha+
205	Isomorphic Strings	Alpha+
290	Word Pattern	Alpha
293	Flip Game	Alpha
294	Flip Game II	Alpha	Recursion
387	First Unique Character in a String	Alpha
383	Ransom Note	Alpha
242	Valid Anagram	Alpha+
49	Group Anagrams	Alpha+
249	Group Shifted Strings	Alpha+
179	Largest Number	Alpha	custom sort
6	ZigZag Conversion	Alpha
161	One Edit Distance	Alpha+
38	Count and Say	Exotic
271	Encode and Decode Strings	Alpha+
168	Excel Sheet Column Title	Exotic
171	Excel Sheet Column Number	Charlie
13	Roman to Integer	Bad
12	Integer to Roman	Bad
246	Strobogrammatic Number	Alpha
247	Strobogrammatic Number II	Charlie
125	Valid Palindrome	Alpha+	two pointers
680	Valid Palindrome II	Alpha+
266	Palindrome Permutation	Alpha
267	Palindrome Permutation II	Alpha+
392	Is Subsequence	Alpha+
792	Number of Matching Subsequence	Alpha+
187	Repeated DNA Sequences	Alpha+
771	Jewels and Stongs	Alpha
844	Backspace String Compare	Alpha
1967	Number of Strings That Appear as Substrings in Word	Alpha+
372	Super Pos	Exotic

Matrix

ID	Name	Rating	Note
48	Rotate Image	Alpha+
54	Spiral Matrix	Alpha+
59	Spiral Matrix II	Alpha+
73	Set Matrix Zeroes	Alpha
311	Sparse Matrix Multiplication	Alpha+
36	Valid Sudoku	Alpha

Math

ID	Name	Rating	Note
7	Reverse Integer	Alpha+
9	Palindrome Number	Alpha+
66	Plus One	Alpha
369	Plus One Linked List	Alpha+
258	Add Digits	Alpha
2	Add Two Numbers	Alpha+
415	Add Strings	Alpha+
67	Add Binary	Alpha+
43	Multiply Strings	Exotic
204	Count Primes	Alpha+
231	Power of Two	Alpha+
326	Power of Three	Alpha
342	Power of Four	Alpha
319	Bulb Switcher	Bravo
292	Nim Game	Exotic
202	Happy Number	Alpha+
263	Ugly Number	Alpha+
264	Ugly Number II	Exotic
313	Super Ugly Number	Exotic
31	Next Permutation	Bravo, Mechanical
60	Permutation Sequence	Exotic
224	Basic Calculator	Alpha	See 772
227	Basic Calculator II	Alpha	See 772
772	Basic Calculator III	Alpha+
50	Pow(x, n)	Alpha
223	Rectangle Area	Bravo	Geometry
1447	Simplified Fractions	Bravo	GCD

Multithreading

ID	Name	Rating	Note
1188	Design Bounded Blocking Queue	Alpha+
1114	Print in Order.cpp	Alpha+
1115	Print FooBar Alternately.cpp	Alpha+
1116	Print Zero Even Odd.cpp	Alpha
1195	Fizz Buzz Multithreaded.cpp	Alpha+

CPP Examples

ID	Name	Rating	Note
N9	Function Pointers	Alpha
N13	Polymorphism	Alpha

Vector Math

ID	Name	Rating	Note
N12	Half Space	Alpha+

Uncategorized

ID	Name	Rating	Note
991	Broken Calculator	Charlie	math
556	Next Greater Element III	Charlie
969	Pancake Sorting	Charlie	recursion
1578	Minimum Deletion Cost to Avoid Repeating Letters	Alpha
995	Minimum Number of K Consecutive Bit Flips	Bravo	greedy
795	Number of Subarrays with Bounded Maximum	Bravo

Bit Manipulation

ID	Name	Rating	Note
289	Game of Life	Alpha
136	Single Number	Alpha
389	Find the Difference	Alpha
137	Single Number II	Bravo, Mechanical
260	Single Number III	Bravo, Mechanical
268	Missing Number	Bravo
191	Number of 1 Bits	Alpha+
190	Reverse Bits	Alpha
201	Bitwise AND of Numbers Range	Bravo

Dynamic Programming

ID	Name	Rating	Note
121	Best Time to Buy and Sell Stock	Alpha+
122	Best Time to Buy and Sell Stock II	Alpha+
123	Best Time to Buy and Sell Stock III	Alpha+
188	Best Time to Buy and Sell Stock IV	Alpha+
309	Best Time to Buy and Sell Stock with Cooldown	Alpha+
714	Best Time to Buy and Sell Stock with Transaction Fee	Alpha+
70	Climbing Stairs	Alpha+
746	Min Cost Climbing Staris	Alpha
120	Triangle	Alpha
279	Perfect Squares	Alpha
322	Coin Change	Alpha+
256	Paint House	Alpha+
265	Paint House II	Alpha+
198	House Robber	Alpha+
213	House Robber II	Alpha
337	House Robber III	Alpha+	postorder
740	Delete and Earn	Alpha
62	Unique Paths	Alpha+
N3	Unique Paths from Top Left to Bottom Right	Alpha+
63	Unique Paths II	Alpha+
64	Minimum Path Sum	Alpha+
221	Maximal Square	Alpha
361	Bomb Enemy	Alpha+
53	Maximum Subarray	Alpha+
152	Maximum Product Subarray	Alpha+
376	Wiggle Subsequence	Alpha+
978	Longest Turbulent Subarray	Alpha
97	Interleaving String	Alpha	2D DP String
44	Wildcard Matching	Bravo	2D DP String, Mechanical
115	Distinct Subsequences	Bravo	2D DP String
139	Word Break	Alpha+	1D DP String
673	Number of Increasing Subsequence	Bravo
300	Longest Increasing Subsequence	Alpha+
354	Russian Doll Envelopes	Alpha+
1143	Longest Common Subsequence	Alpha+
583	Delete Operation for Two Strings	Alpha+
72	Edit Distance	Alpha
516	Longest Palindromic Subsequence	Alpha+
5	Longest Palindromic Substring	Alpha+
1312	Minimum Insertion Steps to Make a String Palindrome	Alpha+
10	Reguar Expression Matching	Alpha
651	4 Keys Keyboard	Alpha
650	2 Keys Keyboard	Alpha
887	Super Egg Drop	Bravo	dynamic programming, binary search
312	Burst Balloons	Bravo
N4	1-0 Knapsack	Alpha	knapsack
416	Partition Equal Subset Sum	Alpha	knapsack
518	Coin Change 2	Alpha	knapsack
494	Target Sum	Alpha+	backtracking, dynamic programming, knapsack
1048	Longest String Chain	Alpha+
1027	Longest Arithmetic Subsequence	Alpha+
727	Minimum Window Subsequence	Bravo