README.md

List of Questions

Note : The Sample_Question_title can be in the format => [<Question_name>](./<path_to_question_folder>)

Sno	Question Title	Status	Key Points
1	Game Of Names	Incomplete
2	Infix to Postfix Expression Conversion
3	Maximum Coin Sum
4	Postfix Evaluvation
5	Premium Game	Incomplete
6	Roadies
7	Self Adjusting List
8	Sequence of Sequence
9	String Permutation
10	Togetherness as a Family
11	Training
12	Minimum Sum in Two Arrays
13	Hard Cash
14	Chef and Railway Stations
15	Tax Slabs
16	ATM (HS08TEST)
17	Pintu and Fruits
18	Allocation
19	Lost Guy Radhu
20	COVID Pandemic and Long Queue
21	Triple Sort
22	Prison Labor Dodgers
23	Don't Get Volunteered
24	En Route Salute
25	Fuel Injection Perfection
26	Find the Access Codes
27	Doomsday Fuel	Needs another Look
28	Chef and Price Control
29	Chef and String
30	Chef and Icecream
31	The Tom and Jerry Game!
32	Even Matrix
33	Bytelandian gold coins
34	Marbles
35	Chef and Demonetisation
36	Number of Groups
37	Increasing Decreasing
38	Chef and Strings
39	Chef and Card Game
40	Ada King
41	Missing a Point
42	Chefina and Swaps
43	Doctor Chef
44	Swayamvar
45	Digit Pairs
46	Sell All the Cars
47	Strange Number
48	Unit GCD	Incomplete
49	Squared Subsequences	Incomplete
50	Vestigium
51	Nesting Depths
52	Parenting Partnering Returns
53	Coronavirus Spread
54	Isolation Centers
55	Chef and Bitwise Product	Incomplete
56	Sorting Vases	Incomplete
57	Ways Of Coloring	Incomplete
58	Necklace Problem	Incomplete
59	Bheem and Permutation	Incomplete
60	Bob Hates XORs	Incomplete
61	Indumanti and Fraction	Incomplete
62	City and Concert	Incomplete
63	Two Sum
64	Add Two Numbers
65	Longest Substring Without Repeating Characters
66	Median of Two Sorted Arrays		Important
67	Reverse Integer
68	Longest Palindromic Substring		Manacher's Algorithm
69	Palindrome Number
70	ZigZag Conversion
71	String to Integer		atoi
72	Container With Most Water		Standard Problem
73	Regular Expression Matching		Regex Matching Using DP
74	Kadane's Algorithm		Kadane's Algorithm Maximum Sum Contiguous Subarray
75	Delete without head pointer
76	Strongly Connected Components		Kosaraju's Algorithm
77	LRU Cache		LRU Cache
78	Kth largest element in a stream
79	Subarray with given sum
80	Count the triplets
81	Missing number in array		XOR Manipulation of stream of numbers
82	Merge Without Extra Space		Important Using Gaps to merge two sorted arrays Calculate number of swaps needed for sorting
83	Rearrange Array Alternately		Encoding numbers using modulus
84	Number of pairs		Python's bisect library
85	Reverse words in a given string
86	Parenthesis Matching
87	Inversion of array		Merge Sort
88	Recursively remove all adjacent duplicates
89	Check if string is rotated by two places
90	Roman Number to Integer		Roman number to integer conversion
91	Finding middle element in a linked list		2 pointers Linked List traversal
92	Match a Substring to String
93	Logical Understanding
94	Programming Convolution		Image Convolutions
95	Programming Padding		Image Padding
96	Square arrays
97	Anagram
98	Sort an array of 0s, 1s and 2s
99	Equilibrium Point
100	Minimum Platforms		Job Scheduling
101	Remove Duplicates
102	Leaders in an array		Time Difference in Array Appending and addition of arrays
103	Reverse array in groups
104	Form a palindrome		Longest Palindromic Subsequence
105	Longest Distinct characters in string
106	Longest Common Prefix in an Array
107	Trapping Rain Water		Trapping Water Problem
108	Chocolate Distribution Problem
109	Stock buy and sell
110	Element with left side smaller and right side greater
111	Convert array into Zig-Zag fashion
112	Spirally traversing a matrix		Matrix Spiral Traversal
113	Largest Number formed from an Array		Merge Sort
114	Rotate a Linked List
115	Reverse a Linked List in groups of given size
116	Intersection Point in Y Shapped Linked Lists		Intersection Point of two Linked Lists
117	Detect Loop in linked list		Floyd's Loop Detection
118	Remove loop in Linked List		Linked-list Loop Detection
119	Nth node from end of linked list		Linked List
120	Flattening a Linked List
121	Merge two sorted linked lists
122	Add two numbers represented by linked lists
123	Check if Linked List is Palindrome
124	Implement Queue using Linked List
125	Implement Stack using Linked List
126	Next Greater Element
127	Queue using two Stacks
128	Stack using two queues
129	Get minimum element from stack		Encoding - Decoding
130	Circular tour		Circular Tour Petrol Pumps
131	First non-repeating character in a stream
132	Rotten Oranges
133	Left View of Binary Tree
134	Maximum of all subarrays of size k		Dequeue Sliding Window Maximum
135	PCM Dilemma
136	Memcached Service
137	Chef and Laddus For Children
138	Students, heights and their IQs	Incomplete
139	Check for BST
140	Bottom View of Binary Tree
141	Vertical Traversal of Binary Tree
142	Level order traversal in spiral form
143	Connect Nodes at Same Level
144	Lowest Common Ancestor in a BST
145	Binary Tree to Double Linked List		Tree InOrder Traversal
146	Symmetric Tree
147	Height of Binary Tree
148	Maximum Path Sum between 2 Leaf Nodes
149	Diameter of Binary Tree
150	Check for Balanced Tree
151	Serialize and Deserialize a Binary Tree
152	Find median in a stream		Heap with Streams
153	Heap Sort		Heap Sort
154	Binary Heap Operations
155	Rearrange characters		Heapq library with custom predicate
156	Merge K sorted linked lists		Heaps
157	Flood fill Algorithm
158	Number of paths		math
159	Combination Sum
160	Special Keyboard		Dynamic Programming Approach
161	Josephus problem		Josephus Problem -- Math + Recursion
162	Sort an array according to the other		Heap + Hash Table
163	Sorting Elements of an Array by Frequency		Custom hybrid sort function in python
164	Largest subarray with Zero sum		Sub-Array Sum
165	Common Elements
166	Find All Four Sum Numbers
167	Swapping pairs make sum equal	Incomplete
168	Depth First Traversal of Graph
169	Breadth First Traversal of Graph
170	Detect cycle in an undirected graph
171	Detect cycle in a directed graph
172	Count distinct elements in every window
173	Array Pair Sum Divisibility Problem
174	Longest consecutive subsequence
175	Array Subset of another array
176	Find all pairs with a given sum
177	Zero Sum Subarrays		Zero Sum Subarray
178	Minimum indexed character
179	Check if two arrays are equal or not
180	Uncommon characters
181	Smallest window containing characters of another string		two-pointers string
182	Check if frequencies can be equal
183	Topological sort		Topological Sort
184	Find the number of islands		Island Find
185	Dijkstra Algorithm		Dijkstra
186	Minimum Swaps to Sort		Minimum swaps for sorting -- Graph
187	Shortest Source to Destination Path in a Grid
188	Find whether path exist
189	Minimum Cost Path		BFS with Min Heap
190	Circle of strings		Modelling array problem into graph Eulerian Circuit
191	Special Matrix	Needs another look	Matrix based
192	Floyd Warshall		Floyd Warshall All Pairs Shortest Path problem
193	Alien Dictionary		Topological Sort
194	Snake and Ladder Problem
195	Find Missing And Repeating		Math
196	Activity Selection		Greedy
197	Choose and Swap
198	Page Faults in LRU		LRU Cache Dequeue
199	Largest number possible
200	Minimize the Heights	Needs another look	Greedy
201	Huffman Decoding		Huffman Encoding
202	Minimum Spanning Tree		Minimum Spanning Tree Greedy
203	Shop in Candy Store
204	Geek collects the balls
205	Maximum Index
206	Consecutive 1's not allowed	New Perspective	Fibonacci Series Dynamic Programming
207	Two numbers with sum closest to zero		Two Pointer
208	Minimum Operations
209	Max length chain		Dynamic Programming
210	Minimum number of Coins
211	Longest Common Substring		Dynamic Programming
212	Longest Increasing Subsequence	New Perspective	Dynamic Programming Binary Search Increasing Subsequence
213	Longest Common Subsequence		Longest Common Subsequence
214	0 - 1 Knapsack Problem		0 - 1 Knapsack Dynamic Programming
215	Maximum sum increasing subsequence		Dynamic Programming Increasing Subsequence
216	Minimum number of jumps
217	Edit Distance		Edit Distance Dynamic Programming
218	Coin Change	New Perspective	Dynamic Programming Partition table Unbounded Knapsack
219	Partition Equal Subset Sum		Partition table Dynamic Programming
220	Smallest Positive missing number
221	Box Stacking		Box Stacking Dynamic Programming
222	Maximize The Cut Segments		Dynamic Programming Rod Cutting
223	Maximum path sum in matrix
224	Minimum sum partition		Important Dynamic Programming
225	Count number of hops		Dynamic Programming Simplified DP array
226	Egg Dropping Puzzle	Needs Another Look New Perspective	Dynamic Programming Egg Drop
227	Optimal Strategy For A Game		Dynamic Programming New Perspective Game Strategy
228	Most frequent word in an array of strings
229	CamelCase Pattern Matching		Trie
230	String Ignorance
231	Shortest Common Supersequence Length		Dynamic Programming
232	Design a tiny URL or URL shortener
233	Find the element that appears once in sorted array
234	Search in a Rotated Array
235	Sum of Middle Elements of two sorted arrays	Incomplete
236	Colorful Strings		Permutation
237	Longest consecutive sequence in Binary tree
238	Lowest Common Ancestor in a Binary Tree
239	K-th element of two sorted Arrays		Simultaneous Multiple Array Divide and Conquer
240	Candies Problem
241	Cross the Buildings
242	Happiest Class
243	Maching Sets
244	Course Registration		Kahn's Algorithm
245	Quick Sort		Quick Sort
246	Generate IP Addresses
247	Word Boggle		Backtracking Trie
248	Rotate Bits
249	Rat in a Maze Problem
250	Solve the Sudoku		Sudoku
251	Count total set bits		Bit based
252	Swap all odd and even bits
253	Maximum subset XOR	Needs another Look	Bitwise Gaussian Elimination
254	N-Queen Problem		N Queen
255	Top View of a Tree
256	Down to Zero II		Modelling Greedy into Dynamic Programming
257	Almost Sorted
258	Queen's Attack II
259	Bigger is Greater
260	Generate Parentheses
261	Is Sudoku Valid
262	X Total Shapes		Graph Coloring
263	Merge k Sorted Arrays		Heaps
264	Prerequisite Tasks		Cycle Detection Graph
265	Min Steps in Infinite Grid		Arrays
266	Minimum Lights to Activate
267	Maximum Sum Triplet	Needs another Look	Arrays
268	Prime Sum
269	Max Non Negative SubArray
270	Perfect Peak of Array
271	Diagonal Traversal of Binary Tree
272	Largest Number		Custom Compare Function
273	First Missing Integer		Array Filtering
274	Merge new interval into NonOverlapping Intervals
275	Next Similar Number		Number Arrangement
276	Rearrange Array		Number Encoding
277	Numbers of length N and value less than K	Partially Incomplete Needs another Look	Dynamic Programming
278	Square Root of Integer		Binary Search
279	Power Function		Square and Multiply
280	WoodCutting Made Easy		Binary Search
281	Matrix Median		Binary Search
282	Preorder to BST
283	Simple Queries	Partially Incomplete Needs another Look
284	Count Element Occurence
285	Divide Integers	Needs another Look	Bit Manipulation
286	Single Number among thrice occuring numbers		Bit Manipulation
287	Min XOR value
288	Stringoholics	Needs another Look
289	Integer To Roman
290	Power of 2		Integer Division using strings
291	Minimum Characters required to make a String Palindromic		Important
292	Pair With Given Difference
293	3 Sum		Important Two Pointers
294	3 Sum Zero		Lookup Table
295	Maximum Ones After Modification
296	Different Bits Sum Pairwise		Bit Manipulation
297	Partition List
298	Insertion Sort List		Linked List Insertion Sort
299	Sort List		Linked List Merge Sort
300	Linked List Cycle
301	Reorder List
302	Sliding Window Maximum
303	MAXSPPROD		Stack
304	Nearest Smaller Element
305	Largest Rectangle in Histogram		Stack
306	Maximal String
307	Gray Code
308	Kth Permutation Sequence
309	Letter Phone
310	Palindrome Partitioning
311	Four Sum
312	Random Copy List		Linked List Clone
313	Fraction		Important Cycle Detection in Numbers
314	Subarray with given XOR		Subarray XOR
315	Subarray with B odd numbers
316	Draw Circle		Pattern
317	Non Repeating Numbers		Important XOR Bit Manipulation
318	First n element XOR
319	Rearrange Groups in Linked List
320	Minimum Integer Points Required for Path Traversal
321	Points on the Straight Line
322	Longest Subarray Length		Subarray
323	Subarray with equal occurences		Subarray
324	Longest Increasing Decreasing Subsequence
325	Smallest sequence with given Primes
326	Repeating Sub-Sequence
327	Regular Expression Match (Asterix and Question Mark)		Regex Matching Using DP Dynamic Programming
328	Maximum Product Subarray		Subarray Two Pointers
329	Recover Binary Search Tree	Incomplete	Binary Search Tree Morris Tree Traversal
330	Unique Subsets
331	Count pairs in array divisible by K
332	Print Anagrams Together
333	Rotate Positive Matrix by 90 degree left		Encoding Matrix
334	Swap Kth nodes from ends Linked List
335	Check if subtree		Sub-tree Verification
336	BST Verification using Preorder Traversal		Pre-order Traversal Binary Search Tree
337	Subset Sum Problem		Subset Dynamic Programming
338	Count of subsets with sum equal to X		Dynamic Programming
339	Robot at the Fair
340	Count Palindrome Sub-Strings of a String		Dynamic Programming Strings
341	Boundary Traversal of binary tree
342	Huffman Encoding		Priority Queue Python Custom Heapq Huffman Encoding
343	Total Decoding Messages
344	Target Sum		Dynamic Programming
345	Number of Coins		Dynamic Programming Unbounded Knapsack
346	Split Array With Same Average	Incomplete	Dynamic Programming
347	Thesaurus		Dynamic Programming Permutations Math
348	Number of subsets with product less than k	Partially Incomplete	Dynamic Programming Meet in the Middle
349	Rod Cutting without fixed lengths		Dynamic Programming Rod Cutting
350	Minimum Cost to Cut a Stick		Dynamic Programming Rod Cutting
351	Largest BST Size
352	Magic Triplets		Two Pointers
353	Magnet Array Problem		Divide and Conquer
354	Water Overflow
355	Count number of substrings	Needs Another Look	Sliding Window
356	Clone a Binary Tree with Random Pointers
357	Occurences of 2 as a digit	Needs Another Look	Number Theory
358	Make Binary Tree From Linked List
359	Construct Tree from Preorder Traversal
360	Leaves to DLL
361	Add all greater values to every node in a BST
362	Stock span problem
363	Kumar and Zoo	Needs Another Look
364	UW Connected Galaxies	Needs Another Look	Graphs
365	Majority Element		Moore's Voting Algorithm
366	Copy Set Bits in Range	Bit Manipulation
367	Longest Increasing Path in a Matrix
368	Maximum sum Rectangle	Partially Incomplete	Kadane Algorithm
369	Capacity To Ship Packages Within D Days		Binary Search
370	Largest subsquare surrounded by X
371	Best Time to Buy and Sell Stock - Single Transactions
372	Best Time to Buy and Sell Stock II - Multiple Transactions
373	Best Time to Buy and Sell Stock III - At most 2 transactions
374	Best Time to Buy and Sell Stock IV - At most k transactions		Important
375	Best Time to Buy and Sell Stock with Cooldown		Needs another Look State Transitions
376	Best Time to Buy and Sell Stock with Transaction Fee		State Transitions
377	Word Search
378	Beautiful Array	Needs Another Look	Important Math
379	Word Break
380	Maximum Intervals Overlap
381	Search in a row-column sorted Matrix
382	Count of sum of consecutives		Math
383	Product Pair
384	Kill Captain America	Incomplete	Graph Topological Sort
385	Euler circuit and Path		Graph
386	Linked List Polynomial Addition
387	Preorder traversal Binary Tree
388	Inorder Traversal Binary Tree
389	Postorder Traversal Binary Tree
390	Time in Heaven	Incomplete
391	Minor DNAs	Incomplete
392	Elections
393	H index		Tree
394	Gas Station		Array Greedy
395	Candy Distribution		Array Greedy Dual Traversal
396	Trapping Rain Water 2D		Array Matrix Graph
397	Text Justification		String
398	Rotate Matrix by 90 degrees right		Matrix Encoding
399	Tuple with Same Product		Counting
400	Substring with Concatenation of All Words		String Sliding Window
401	Separate Squares		Binary Search
402	Reschedule Meetings for Maximum Free Time I
403	Meeting Scheduler
404	Reschedule Meetings for Maximum Free Time II
405	Coin Change II
406	Maximal Square		matrix
407	Recover a Tree From Preorder Traversal
408	Design a Number Container System
409	Maximum Sum Subarray with negative numbers		Kandane Divide and Conquer
410	Number of Islands in 4 Direction
411	Clone Undirected Graph
412	Pacific Atlantic Water Flow		matrix
413	Course Schedule II		Graph
414	Course Schedule III		Greedy
415	Graph Valid Tree		Graph Sets Union Find
416	Number of Connected Components in an Undirected Graph		Graph Union Find
417	Paths in Maze That Lead to Same Room		Graph Count Fixed Length Cycles Set Intersection
418	Generate Parentheses
419	Count Number of Bad Pairs
420	Next Permutation
421	Product of the Last K Numbers		Stream
422	Implement Trie (Prefix Tree)		Trie
423	Word Search II		Trie DFS Matrix
424	Merge Intervals		Intervals
425	Minimize Connected Groups by Inserting Interval		Intervals
426	Meeting Rooms		Intervals
427	Meeting Rooms II		Intervals
428	Meeting Rooms III		Intervals
429	Nim Game		Game Theory Math
430	Flip Game II	Incomplete	Game Theory Dynamic Programming Backtracking
431	Climbing Stairs		Combinatorics Dynamic Programming Math
432	House Robber
433	House Robber II
434	House Robber III
435	House Robber IV		Binary Search
436	Find Local Peak Element		Binary Search
437	Find Minimum in Rotated Sorted Array		Binary Search
438	Find First and Last Position of Element in Sorted Array		Binary Search
439	Find K Closest Elements		Binary Search
440	Closest Binary Search Tree Value
441	Search in a Sorted Array of Unknown Size		Binary Search
442	Pow(x, n)		Binary Search
443	Find Minimum in Rotated Sorted Array II		Binary Search
444	Find the Duplicate Number		Bit Manipulation
445	License Key Formatting
446	Fruit Into Baskets		Sliding Window
447	Odd Even Jump	Incomplete
448	Jump Game		Sliding Window
449	Jump Game II		Sliding Window
450	Jump Game III		BFS
451	Jump Game VII		Sliding Window Dynamic Programming
452	Jump Game VIII		Dynamic Programming
453	Jump Game VI		Dynamic Programming Heaps Dequeue
454	Jump Game IV		Dynamic Programming BFS
455	Jump Game V		DFS Dynamic Programming
456	Linked List Cycle II
457	Next Greater Element I
458	Next Greater Element II
459	Next Greater Element III
460	Moving Average from Data Stream
461	Binary Tree Vertical Order Traversal
462	Binary Tree Right Side View
463	Russian Doll Envelopes		Longest Increasing Subsequence
464	Unique Length-3 Palindromic Subsequences
465	Reorganize String
466	Three Sum Closest
467	Single Element in a Sorted Array
468	Counting Bits		Bit Patterns
469	Geek's Training
470	Unique Paths
471	Unique Paths II
472	Minimum Path Sum
473	Partition Array Into Two Arrays to Minimize Sum Difference		Meet in the middle Subset Enumeration Bitmask Enumeration
474	Perfect Sum Problem		Dynamic Programming
475	Partitions with Given Difference		Dynamic Programming
476	Maximum Matching of Players With Trainers
477	Longest Palindromic Subsequence		Dynamic Programming
478	Shortest Common Supersequence Word		Dynamic Programming
479	Distinct Subsequences		Dynamic Programming
480	Largest Divisible Subset		Longest Increasing Subsequence
481	Longest String Chain		Strings Longest Increasing Subsequence
482	Maximal Rectangle Area		Matrix
483	Count Square Submatrices with All Ones		Matrix
484	Palindrome Partitioning II	Strings
485	Interleaving String		Dynamic Programming Strings
486	Queue Reconstruction by Height	Needs another look
487	Next Smallest Palindrome		Pattern Recognition
488	Split Array Largest Sum		Binary Search
489	N/3 Repeat Number		Counting Voting Array
490	Remove K Digits		Monotonic Stack
491	Create Maximum Number		Greedy Monotonic Stack
492	Stream of Characters		Trie
493	Group Anagrams
494	Binary Tree Maximum Path Sum
495	Zero Array Transformation I	New Perspective	Array Prefix Sum
496	Zero Array Transformation II		Array Prefix Sum Binary Search
497	Move Pieces to Obtain a String	Partially Complete	Strings
498	Identify the Largest Outlier in an Array
499	Count Special Subsequences
500	Random Pick with Weight		Random Binary Search Prefix Sum
501	Find Eventual Safe States		Graph Topological Sort
502	Number of Operations to Make Network Connected		Graph Union Find
503	Kth Smallest Element in a Sorted Matrix	Different Perspective Partially Complete	Binary Search Matrix
504	Swim in Rising Water		Graph Heap
505	Detonate the Maximum Bombs		Graph
506	Network Delay Time		Graph Bellman Ford
507	Find the Safest Path in a Grid		Graph Binary Search Matrix Dijkstra
508	Find Closest Node to Given Two Nodes
509	Maximize the Number of Target Nodes After Connecting Trees I
510	Lexicographically Smallest Equivalent String		Union Find
511	Find the Original Typed String II		Dynamic Programming Strings
512	Critical Connections in a Network		Graph Tarjan's Algorithm DFS
513	Snapshot Array		Array, Binary Search Design
514	Maximize the Number of Target Nodes After Connecting Trees II		Graph
515	Min Stack
516	Binary Search Tree Iterator
517	Peeking Iterator
518	Range Sum Query 2D - Immutable
519	Range Sum Query - Mutable		Segment Tree
520	Word Pattern
521	Shuffle an Array		Randomness
522	Remove Nth Node From End of List		Linked List
523	Maximum Level Sum of a Binary Tree		Binary Tree
524	Longest Repeating Character Replacement		Sliding Window
525	Binary Subarrays With Sum	New Perspective	Prefix Sum Sliding Window At-most trick
526	Count Number of Nice Subarrays		Sliding Window At-most trick
527	Minimum Window Substring		Sliding Window
528	Search Insert Position in Arrays
529	Koko Eating Bananas		Binary Search
530	Daily Temperatures		Monotonic Stack
531	Palindrome Linked List
532	Reverse Nodes in k-Group		Linked List Node Reversal
533	Binary Tree Target Path Sum
534	Binary Tree Level Order Traversal
535	Binary Tree Zigzag Level Order Traversal		deque
536	Validate Binary Search Tree
537	Kth Smallest Element in a BST
538	Convert Sorted Array to Binary Search Tree
539
540
541
542
543
544
545
546
547
548
549
550