POTD Solutions

GeeksforGeeks Java Solutions

Java solutions for GeeksforGeeks problems with step-by-step explanations on 204+ problems, plus approach notes and complexity analysis across the full archive.

714

Solved

204

Explained

LeetCode C#Topics Study Guide

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