POTD Solutions

GeeksforGeeks Java Solutions

Java solutions for GeeksforGeeks problems with step-by-step explanations on 605+ problems, plus approach notes and complexity analysis across the full archive.

606

Solved

605

Explained

LeetCode C#Topics Study Guide

606 problemsFull explanation available

#	Title
1	0 - 1 Knapsack Problem
2	1s Surrounded by 0s
3	2D Difference Array
4	2D Submatrix Sum Queries
5	Activity Selection
6	Add 1 to a Linked List Number
7	Add Binary Strings
8	Add Number Linked Lists
9	Aggressive Cows
10	Alien Dictionary
11	All numbers with specific difference
12	All Subsets Xor Sum
13	All Unique Permutations of an array
14	Allocate Minimum Pages
15	Alternate positive and negative numbers
16	Alternative Sorting
17	Anagram
18	Anagram Palindrome
19	Ancestors in Binary Tree
20	AND In Range
21	Array Duplicates
22	Array to BST
23	Articulation Point - II
24	ASCII Range Sum
25	Assign Mice Holes
26	Balancing Consonants and Vowels Ratio
27	Bellman-Ford
28	BFS of graph
29	Binary Searchable Count
30	Binary Strings with Equal Sum of Two Halves
31	Binary Tree to DLL
32	Bitonic Point
33	Boolean Parenthesization
34	Bottom View of Binary Tree
35	Brackets in Matrix Chain Multiplication
36	Bridge edge in a graph
37	BST to greater sum tree
38	BST with Dead End
39	Buildings with Sunlight
40	Burning Tree
41	Bus Conductor
42	Bus Ticket Change
43	Buy Stock with Transaction Fee
44	Candy
45	Case-specific Sorting of Strings
46	Check for BST
47	Check for Power
48	Check if a String is Subsequence of Other
49	Check if an Array is Max Heap
50	Check if frequencies can be equal
51	Check if subtree
52	Check If two Line segments Intersect
53	Check Repeated Substring with K Replacements
54	Chocolate Distribution Problem
55	Chocolate Pickup II
56	Chocolates Pickup
57	Circle of strings
58	Clone a linked list with next and random pointer
59	Clone an Undirected Graph
60	Clone List with Next and Random
61	Closest Neighbour in BST
62	Closest Three Sum
63	Coin Change (Count Ways)
64	Coin Change (Minimum Coins)
65	Coin Piles
66	Common in 3 Sorted Arrays
67	Compare two fractions
68	Consecutive 1's not allowed
69	Construct an array from its pair-sum array
70	Construct Binary Tree from Parent Array
71	Construct List using XOR Queries
72	Construct Tree from Inorder & Preorder
73	Construct Tree from Preorder & Postorder
74	Container With Most Water
75	Count all triplets with given sum in sorted array
76	Count Derangements
77	Count distinct elements in every window
78	Count elements less than or equal to k in a sorted rotated array
79	Count increasing Subarrays
80	Count Indices to Balance Even and Odd Sums
81	Count Inversions
82	Count Linked List Nodes
83	Count Numbers Containing Specific Digits
84	Count of distinct substrings
85	Count pairs Sum in matrices
86	Count Pairs whose sum is less than target
87	Count pairs with given sum
88	Count Reverse Pairs
89	Count set bits
90	Count Smaller elements
91	Count Sorted Digit Groupings
92	Count Spanning Trees in a Graph
93	Count Subarray with k odds
94	Count Subarrays with given XOR
95	Count Subset With Target Sum II
96	Count the Coprimes
97	Count the number of possible triangles
98	Count the paths
99	Count Unique Vowel Strings
100	Count ways to N'th Stair(Order does not matter)
101	Count X in Range of a Sorted Array
102	Counting elements in two arrays
103	Course Schedule I
104	Course Schedule II
105	Coverage of all Zeros in a Binary Matrix
106	Cut rope to maximise product
107	Cutting Binary String
108	Decode the string
109	Delete Alternate Nodes
110	Delete node in Doubly Linked List
111	Delete Nodes with Greater on Right
112	Deletion and Reverse in Circular Linked List
113	Design MinMax Queue
114	Detect Loop in linked list
115	DFS of Graph
116	Diameter of a Binary Tree
117	Dice throw
118	Difference Check
119	Dijkstra Algorithm
120	Directed Graph Cycle
121	Distance of nearest cell having 1
122	Distribute Candies
123	Divisible by 13
124	Duplicate Subtrees
125	Edit Distance
126	Elements in range [a, b]
127	Elements in the Range
128	Equal Point in Brackets
129	Equalize All Prefix Sums
130	Equalize the Towers
131	Equilibrium Point
132	Evaluation of Postfix Expression
133	Exactly one swap
134	Exit Point in a Matrix
135	Express as Consecutive Number Sum
136	Expression Add Operators
137	Expression contains redundant bracket or not
138	Extract the Number from the String
139	Facing the sun
140	Farthest Smaller Right
141	Find all possible palindromic partitions of a String
142	Find All Triplets with Zero Sum
143	Find H-Index
144	Find K Smallest Sum Pairs
145	Find Kth Rotation
146	Find length of Loop
147	Find maximum volume of a cuboid
148	Find median in a stream
149	Find Only Repetitive Element from 1 to n-1
150	Find rectangle with corners as 1
151	Find the closest pair from two arrays
152	Find the first node of loop in linked list
153	Find the longest string
154	Find the number of islands
155	Find the Sum of Last N nodes of the Linked List
156	Finding Profession
157	Fixing Two nodes of a BST
158	Flattening a Linked List
159	Flip to Maximize 1s
160	Flood fill Algorithm
161	Floyd Warshall
162	Form a palindrome
163	Form the Largest Number
164	Frog Jump
165	Game of XOR
166	Game with String
167	Gas Station
168	Generate all binary strings
169	Generate Binary Numbers
170	Generate IP Addresses
171	Generate Permutations of an array
172	Get Min from Stack
173	Get Minimum Squares
174	Gold Mine Problem
175	Graph Diameter
176	Gray Code
177	Group Balls by Sequence
178	Happiest Triplet
179	Height of Binary Tree
180	Histogram Max Rectangular Area
181	Huffman Encoding
182	Identical Linked Lists
183	Implement Atoi
184	Implement k Queues in a Single Array
185	Implement Pow
186	Implement Trie
187	Indexes of Subarray Sum
188	Inorder Traversal
189	Insert in Sorted Circular Linked List
190	Insert in Sorted way in a Sorted DLL
191	Insert Interval
192	Integral Points Inside Triangle
193	Interleave the First Half of the Queue with Second Half
194	Interleaved Strings
195	Intersection in Y Shaped Lists
196	Intersection of Two arrays with Duplicate Elements
197	Intersection of Two Sorted Arrays
198	Intersection Point in Y Shaped Linked Lists
199	Is Binary Tree Heap
200	Is Linked List Length Even
201	Job Sequencing Problem
202	Josephus problem
203	K closest elements
204	K Closest Points to Origin
205	K closest Values
206	k largest elements
207	K Sized Subarray Maximum
208	K Sum Paths
209	K-Pangrams
210	K-th element of two Arrays
211	K-th Largest Sum Contiguous Subarray
212	k-th Smallest in BST
213	Kadane's Algorithm
214	Koko Eating Bananas
215	Kth distance
216	Kth element in Matrix
217	Kth Largest in a Stream
218	Kth Missing Positive Number in a Sorted Array
219	Kth Smallest
220	Kth Smallest Number in Multiplication Table
221	Largest BST
222	Largest Divisible Subset
223	Largest number in K swaps
224	Largest number in one swap
225	Largest Pair Sum
226	Largest square formed in a matrix
227	Largest subarray of 0's and 1's
228	Last Coin in a Game of Alternates
229	Last Digit of a^b
230	Last Moment Before All Ants Fall Out
231	LCM Triplet
232	LCS of three strings
233	Left Rotate Matrix K times
234	Left View of Binary Tree
235	Length of Longest Cycle in a Graph
236	Level Order in spiral form
237	Level order traversal
238	Lexicographically Largest String After Deleting K Characters
239	Lexicographically smallest after removing k
240	Linked List Group Reverse
241	Linked List Matrix
242	Linked list of strings forms a palindrome
243	Longest alternating subsequence
244	Longest Bounded-Difference Subarray
245	Longest Common Increasing Subsequence
246	Longest Common Prefix of Strings
247	Longest Common Subsequence
248	Longest Common Substring
249	Longest Consecutive Subsequence
250	Longest Increasing Subsequence
251	Longest Palindrome in a String
252	Longest Palindromic Subsequence
253	Longest Periodic Proper Prefix
254	Longest Prefix Suffix
255	Longest Repeating Character Replacement
256	Longest Span in two Binary Arrays
257	Longest String Chain
258	Longest Subarray Length
259	Longest subarray with Atmost two distinct integers
260	Longest Subarray with Majority Greater than K
261	Longest Subarray with Sum K
262	Longest substring with distinct characters
263	Longest Substring with K Uniques
264	Longest valid Parentheses
265	Look and Say Pattern
266	Lowest Common Ancestor in a BST
267	LRU Cache
268	Majority Element
269	Majority Element II
270	Majority Vote
271	Make array elements unique
272	Make Binary Tree From Linked List
273	Make Matrix Beautiful
274	Make Strings Equal
275	Make the array beautiful
276	Matrix Chain Multiplication
277	Max Circular Subarray Sum
278	Max DAG Edges
279	Max distance between same elements
280	Max min Height
281	Max of min for every window size
282	Max Product Subset
283	Max Profit from Two Machines
284	Max rectangle
285	Max Score from Subarray Mins
286	Max sum in the configuration
287	Max Sum Increasing Subsequence
288	Max sum path in two arrays
289	Max Sum Subarray of size K
290	Max Xor Subarray of size K
291	Maximise String Score
292	Maximize Array Value After Rearrangement
293	Maximize median after doing k addition operation
294	Maximize Number of 1's
295	Maximize partitions in a String
296	Maximize The Cut Segments
297	Maximize the minimum difference between k elements
298	Maximum Connected group
299	Maximum Difference
300	Maximum Non-Adjacent Nodes Sum
301	Maximum Non-Overlapping Odd Palindrome Sum
302	Maximum number of overlapping Intervals
303	Maximum of minimum for every window size
304	Maximum path sum
305	Maximum path sum from any node
306	Maximum People Visible in a Line
307	Maximum Product Subarray
308	Maximum product subset of an array
309	Maximum Stone Removal
310	Maximum subarray sum 2
311	Maximum Sum Combination
312	Maximum sum of elements not part of LIS
313	Maximum sum of Non-adjacent nodes
314	Maximum Sum Problem
315	Maximum sum Rectangle
316	Maximum XOR of two numbers in an array
317	Mean of range in array
318	Median in a row-wise sorted Matrix
319	Median of BST
320	Median of two sorted arrays
321	Meeting Rooms
322	Meeting Rooms III
323	Merge K sorted linked lists
324	Merge Sort for Linked List
325	Merge two BST 's
326	Merge two sorted linked lists
327	Merge Without Extra Space
328	Middle of a Linked List
329	Min Add to Make Parentheses Valid
330	Min Chars to Add for Palindrome
331	Min Cost Climbing Stairs
332	Min Swaps to Group 1s
333	Minimal Cost
334	Minimize the Heights I
335	Minimize the Heights II
336	Minimum Cost of ropes
337	Minimum Cost Path
338	Minimum cost to connect all houses in a city
339	Minimum Cost to cut a board into squares
340	Minimum Cost to Cut a Stick of length N
341	Minimum Cost to Fill Given Weight
342	Minimum Cost to Merge Stones
343	Minimum days to make M bouquets
344	Minimum Deletions
345	Minimum height roots
346	Minimum Jumps
347	Minimum K Consecutive Bit Flips
348	Minimum Multiplications to reach End
349	Minimum number of deletions and insertions
350	Minimum Number of Workers
351	Minimum Operations to Connect Hospitals
352	Minimum Platforms
353	Minimum repeat to make substring
354	Minimum Steps to Halve Sum
355	Minimum sum
356	Minimum Toggle to Partition
357	Minimum Weight Cycle
358	Minimum Window Subsequence
359	Mirror Tree
360	Missing And Repeating
361	Missing Element in Range
362	Missing element of AP
363	Missing in Array
364	Mobile numeric keypad
365	Modify the Array
366	Mother Vertex
367	Move All Zeroes to End
368	Multiply two linked lists
369	Multiply two strings
370	N meetings in one room
371	N-Queen Problem
372	nCr
373	Nearest multiple of 10
374	Nearly sorted
375	Next element with greater frequency
376	Next Greater Element
377	Next Greater Element in Circular Array
378	Next Permutation
379	Next Smallest Palindrome
380	Nine Divisors
381	Non Repeating Character
382	Non-Attacking Black and White Knights
383	Non-overlapping Intervals
384	Not a subset sum
385	Nth Natural Number
386	Number of BST From Array
387	Number of distinct subsequences
388	Number of occurrence
389	Number of pairs
390	Number of paths in a matrix with k coins
391	Number of Rectangles in a Circle
392	Number of Ways to Arrive at Destination
393	Occurence of an integer in a Linked List
394	Opposite Sign Pair Reduction
395	Optimal binary search tree
396	Optimal Strategy For A Game
397	Overlapping Intervals
398	Painting the Fence
399	Pair Sum in BST
400	Pair with given sum in a sorted array
401	Pairs with certain difference
402	Pairs with difference k
403	Palindrome Linked List
404	Palindrome Pairs
405	Palindrome Sentence
406	Palindrome SubStrings
407	Parenthesis Checker
408	Partition Equal Subset Sum
409	Partitions with Given Difference
410	Pascal Triangle
411	Path With Minimum Effort
412	Peak element
413	Permutations of a String
414	Police and Thieves
415	Populate Inorder Successor for all nodes
416	Possible Words From Phone Digits
417	Postfix Evaluation
418	Postorder Traversal
419	Power of k in factorial of n
420	Powerful Integer
421	Predecessor and Successor
422	Prime List
423	Prime Pair with Target Sum
424	Print Anagrams Together
425	Print Bracket Number
426	Print Diagonally
427	Print leaf nodes from preorder traversal of BST
428	Product array puzzle
429	Product Pair
430	Pythagorean Triplet
431	Queue Reversal
432	Quick Sort on Linked List
433	Range LCM Queries
434	Rat in a Maze
435	Rat in a Maze Problem - I
436	Remaining String
437	Remove all occurences of duplicates in a linked list
438	Remove BST keys outside given range
439	Remove Duplicates
440	Remove duplicates in array
441	Remove Half Nodes
442	Remove Invalid Parentheses
443	Remove loop in Linked List
444	Remove Spaces
445	Remove the balls
446	Reorganize The Array
447	Replace O's with X's
448	Replace with XOR of Adjacent
449	Reverse a Doubly Linked List
450	Reverse a linked list
451	Reverse an Array
452	Reverse Words
453	Roman Number to Integer
454	Roof Top
455	Root to leaf path sum
456	Root to Leaf Paths
457	Root to leaf paths sum
458	Rotate a Linked List
459	Rotate and delete
460	Rotate Array
461	Rotate by 90 degree
462	Rotate Deque By K
463	Rotten Oranges
464	Row with max 1s
465	Safe States
466	Search for Subarray
467	Search in a Row-Column sorted matrix
468	Search in a row-wise sorted matrix
469	Search in a sorted Matrix
470	Search in an almost Sorted Array
471	Search in fully rotated sorted 2D matrix
472	Search in Rotated Sorted Array
473	Search insert position of K in a sorted array
474	Search Pattern (KMP-Algorithm)
475	Search Pattern (Rabin-Karp Algorithm)
476	Seating Arrangement
477	Second Best Minimum Spanning Tree
478	Second Largest
479	Segregate 0s and 1s
480	Serialize and deserialize a binary tree
481	Set Matrix Zeroes
482	Set Matrix Zeros
483	Shop in Candy Store
484	Shortest Common Supersequence
485	Shortest Cycle
486	Shortest path in Undirected Graph
487	Shortest Path in Weighted undirected graph
488	Shortest Path Using Atmost One Curved Edge
489	Single Number
490	Size of Binary Tree
491	Smallest distinct window
492	Smallest Divisor
493	Smallest number
494	Smallest Positive Missing
495	Smallest Positive Missing Number
496	Smallest range in K lists
497	Smallest window containing 0, 1 and 2
498	Smallest window containing all characters
499	Smallest window in a string containing all the characters of another string
500	Solve the Sudoku
501	Sort 0s, 1s and 2s
502	Sort a k sorted doubly linked list
503	Sort a linked list of 0s, 1s and 2s
504	Sort by Absolute Difference
505	Sort in specific order
506	Sort the given array after applying the given equation
507	Sorted and Rotated Minimum
508	Sorted subsequence of size 3
509	Sorting Elements of an Array by Frequency
510	Spirally traversing a matrix
511	Split an array into two equal Sum subarrays
512	Split array in three equal sum subarrays
513	Split Array Largest Sum
514	Split Array Subsequences
515	Split Linked List Alternatingly
516	Split the Array
517	Square root of a number
518	Stable Marriage Problem
519	Stickler Thief
520	Stickler Thief II
521	Stock Buy and Sell – Max 2 Transactions Allowed
522	Stock Buy and Sell – Max K Transactions Allowed
523	Stock Buy and Sell – Max one Transaction Allowed
524	Stock Buy and Sell – Multiple Transaction Allowed
525	Stock Buy and Sell with Cooldown
526	Stock span problem
527	Stream First Non-repeating
528	String stack
529	Strings Rotations of Each Other
530	Sub-arrays with equal number of occurences
531	Subarray Frequency Count Queries
532	Subarray range with given sum
533	Subarrays With At Most K Distinct Integers
534	Subarrays with First Element Minimum
535	Subarrays with sum K
536	Subset Sum Problem
537	Subset XOR
538	Substring with Max Zero-One Diff
539	Substrings of length k with k-1 distinct elements
540	Substrings with K Distinct
541	Substrings with same first and last characters
542	Sum of all substrings of a number
543	Sum of Mode
544	Sum of Nodes in BST Range
545	Sum of nodes on the longest path
546	Sum of subarray minimum
547	Sum of subarray minimums
548	Sum of subarray ranges
549	Sum of Subarrays
550	Sum of XOR of all pairs
551	Sum Pair closest to target
552	Sum Tree
553	Sum-string
554	Summed Matrix
555	Swap and Maximize
556	Swap diagonals
557	Swap Kth nodes from ends
558	Symmetric Tree
559	Target Sum
560	The Celebrity Problem
561	The Knight's tour problem
562	The Painter's Partition Problem-II
563	The Palindrome Pattern
564	Toeplitz matrix
565	Top K Frequent in Array
566	Top View of Binary Tree
567	Topological sort
568	Total count
569	Total Decoding Messages
570	Trail of ones
571	Transform to Sum Tree
572	Transpose of Matrix
573	Trapping Rain Water
574	Travelling Salesman Problem
575	Tree Boundary Traversal
576	Triplet Family
577	Two Equal Sum Subarrays
578	Two Smallests in Every Subarray
579	Two Sum - Pair with Given Sum
580	Two Swaps
581	Two water Jug problem
582	Tywin's War Strategy
583	Undirected Graph Cycle
584	Union of Arrays with Duplicates
585	Union of Two Sorted Arrays with Distinct Elements
586	Unique K-Number Sum
587	Unique Number I
588	Unique Number II
589	Unique Number III
590	Unique Paths in a Grid
591	URLify a given string
592	Validate an IP Address
593	Vertical Sum
594	Vertical Tree Traversal
595	Vertical Width of a Binary Tree
596	Walls Coloring II
597	Ways to Reach the n'th Stair
598	Ways To Tile A Floor
599	Weighted Job Scheduling
600	Wifi Range
601	Wildcard Pattern Matching
602	Word Break
603	Word Search
604	XOR Linked List
605	XOR Pairs less than K
606	ZigZag Tree Traversal