Leetcode Solutions Java

This is a personal journey to leetcode of Kumar Pallav . The solutions are mostly in Java.

String

No	Question	Level	Solution
520	Detect Capital	Easy	DetectCapital
1221	Split a String in Balanced Strings	Easy	SplitaStringinBalancedStrings
345	Reverse Vowels of a String	Easy	ReverseVowelsofaString
344	Reverse String	Easy	ReverseString
804	Unique Morse Code Words	Easy	UniqueMorseCodeWords
1436	Destination City	Easy	DestinationCity
859	Buddy Strings	Easy	BuddyString
316	Remove Duplicate Letters	Easy	RemoveDuplicateLetters
819	Most Common Word	Easy	MostCommonWord
1002	Find Common Characters	Easy	FindCommonCharacters
1446	Consecutive Characters	Easy	ConsecutiveCharacters
1614	Maximum Nesting Depth of the Parentheses	Easy	MaximumNestingDepthoftheParentheses
1370	Increasing Decreasing String	Easy	MaximumNestingDepthoftheParentheses
1662	Check If Two String Arrays are Equivalent	Easy	CheckIfTwoStringArraysareEquivalent
809	Expressive Words	Medium	ExpressiveWords
/1694/Reformat Phone Number	ReformatPhoneNumber
1704	Determine if String Halves Are Alike	Easy	DetermineifStringHalvesAreAlike

Arrays

No	Question	Level	Solution

| 1480 | Running Sum of 1d Array|Easy| RunningSumof1dArray| | 1431 | Kids With the Greatest Number of Candies|Easy |KidsWithTheGreatestNumberofCandies| | 1309 |Decrypt String from Alphabet to Integer Mapping|Easy|DecryptStringfromAlphabettoIntegerMapping| | 1389 |Create Target Array in the Given Order |Easy | CreateTargetArrayintheGivenOrder| | 1450 |Number of Students Doing Homework at a Given Time |Easy | NumberofStudentsDoingHomeworkataGivenTime| | 1313 | Decompress Run-Length Encoded List| Easy | DecompressRunLengthEncodedList| | 220 |Contains Duplicate III|Medium | ContainsDuplicateIII| |1380| Lucky Numbers in a Matrix| Easy |LuckyNumbersinaMatrix| |682| Baseball Game| Easy |Baseball Game| | 1572 | Matrix Diagonal Sum|Easy| MatrixDiagonalSum| |389 |Find the Difference| Easy | FindtheDifference| |977| Squares of a Sorted Array| Easy |SquaresofaSortedArray| | 1295 | Find Numbers with Even Number of Digits|Easy| FindNumberswithEvenNumberofDigits| |1266 |Minimum Time Visiting All Points| Easy | MinimumTimeVisitingAllPoints| |202| Happy Number| Easy | HappyNumber| |1588| Sum of All Odd Length Subarrays| Easy | SumofAllOddLengthSubarrays| |39| CombinationSum | Medium | CombinationSum| |1288| Remove Covered Intervals| Medium | RemoveCoveredIntervals| |1464| Maximum Product of Two Elements in an Array| Easy | MaximumProductofTwoElementsinanArray| |832| Flipping an Image| Easy | FlippinganImage| |1051|Height Checker|Easy|HeightChecker| |1351|Count Negative Numbers in a Sorted Matrix|Easy|CountNegativeNumbersinaSortedMatrix| |189|Rotate Array| Medium | RotateArray| |1486| XOR Operation in an Array| Easy| XOROperationinanArray| |1252|Cells with Odd Values in a Matrix| Easy| CellwithOddValuesinaMatrix| |41|First Missing Positive|Hard | FirstMissingPositive| |74|Search a 2D Matrix|Medium | Searcha2DMatrix| |1299|Replace Elements with Greatest Element on Right Side|Easy | ReplaceElementswithGreatestElementonRightSide| |238| Product of Array Except Self|Medium | ProductofArrayExceptSelf| |1329|Sort the Matrix Diagonally|Medium | SorttheMatrixDiagonally| |532|K-diff Pairs in an Array|Medium | KdiffPairsinanArray| |1460| Make Two Arrays Equal by Reversing Sub-arrays| Easy| MakeTwoArraysEqualbyReversingSubarrays| |228| Summary Ranges| Easy| SummaryRanges| |118| Pascal's Triangle| Easy| PascalsTriangle| |849| Maximize Distance to Closest Person| Medium | MaximizeDistancetoClosestPerson| |419|Battleships in a Board|Medium| BattleshipsinaBoard| |1476|Subrectangle Queries|Medium|SubrectangleQueries| |1640|Check Array Formation Through Concatenation | Easy| CheckArrayFormationThroughConcatenation| |1304| Find N Unique Integers Sum up to Zero|Easy| FindNUniqueIntegersSumuptoZero| |1637| Widest Vertical Area Between Two Points Containing No Points | Medium | WidestVerticalAreaBetweenTwoPointsContainingNoPoints| |845|Longest Mountain in Array| Medium | LongestMountaininArray| |56|Merge Intervals | Medium | MergeIntervals| |48|Rotate Image|Medium| RotateImage| |53| Maximum Subarray|Easy| MaximumSubarray| |1222| Queens That Can Attack the King|Medium | QueensThatCanAttacktheKing| |75| Sort Colors | Medium | SortColors| |283|Move Zeroes | Medium | MoveZeroes| |15|3Sum|Medium| ThreeSum| |217|Contains Duplicate|Easy| ContainsDuplicate| |4|Median of Two Sorted Arrays|Hard| MedianofTwoSortedArrays| |287|Find the Duplicate Number|Medium| FindtheDuplicateNumber| |448|Find the Duplicate Number|Easy| FindAllNumbersDisappearedinanArray| |442|Find All Duplicates in an Array|Medium| FindAllDuplicatesinanArray |169|Majority Element|Easy| MajorityElement| |1710|Maximum Units on a Truck|Easy| MaximumUnitsonaTruck| |1711|Count Good Meals|Medium| CountGoodMeals| |457|Circular Array Loop|Medium| CircularArrayLoop|

Stack

No	Question	Level	Solution
125	Valid Palindrome	Easy	ValidPalindrome
1021	Remove Outermost Parentheses	Easy	RemoveOutermostParentheses
1047	Remove All Adjacent Duplicates In String	Easy	RemoveAllAdjacentDuplicatesInString
496	Next Greater Element I	Easy	NextGreaterElementI
1544	Make The String Great	Easy	MakeTheStringGreat
232	Implement Queue using Stacks	Easy	ImplementQueueusingStacks
844	Backspace String Compare	Easy	BackspaceStringCompare
155	Min Stack	Easy	MinStack
20	Valid Parentheses	(Easy)	ValidParentheses
1190	Reverse Substrings Between Each Pair of Parentheses	Easy	ReverseSubstringsBetweenEachPairofParentheses
1249	Minimum Remove to Make Valid Parentheses		MinimumRemovetoMakeValidParentheses
921	Minimum Add to Make Parentheses Valid	Medium	MinimumAddtoMakeParenthesesValid
735	Asteroid Collision	Medium	AsteroidCollison
456	132 Pattern	Medium	_132Pattern
1381	Design a Stack With Increment Operation	Medium	DesignaStackWithIncrementOperation
394	Decode String	Medium	DecodeString
1598	Crawler Log Folder	Easy	CrawlerLogFolder
227	Basic Calculator II	Medium	BasicCalculatorII
1541	Minimum Insertions to Balance a Parentheses String	Medium	MinimumInsertionstoBalanceaParenthesesString

LinkedList

No	Question	Level	Solution
876	Middle of the Linked List	Easy	MiddleoftheLinkedList
237	Delete Node in a Linked List	Easy	DeleteNodeinaLinkedList
206	Reverse Linked List	Easy	ReverseLinkedList
21	Merge Two Sorted Lists	Easy	MergeTwoSortedLists
83	Remove Duplicates from Sorted List	Easy	RemoveDuplicatesfromSortedList
141	Linked List Cycle	Easy	LinkedListCycle
142	Linked List Cycle II	Medium	LinkedListCycleII
160	Intersection of Two Linked Lists	Easy	IntersectionofTwoLinkedLists
328	Odd Even Linked List	Easy	OddEvenLinkedList
725	Split Linked List in Parts	Easy	SplitLinkedListinParts
1019	Next Greater Node In Linked List	Easy	NextGreaterNodeInLinkedList
234	Palindrome Linked List		PalindromeLinkedList
24	Swap Nodes in Pairs		SwapNodesinPairs
109	Convert Sorted List to Binary Search Tree	Medium	ConvertSortedListtoBinarySearchTree
61	Rotate List	Medium	RotateList
2	Add Two Numbers	Medium	AddTwoNumbers
148	Sort List	Medium	SortList
1290	Convert Binary Number in a Linked List to Integer	Easy	ConvertBinaryNumberinaLinkedListtoInteger
147	Insertion Sort List	Medium	InsertionSortList
445	Add Two Numbers II	Medium	AddTwoNumbersII
382	Linked List Random Node	MEDIUM	LinkedListRandomNode
1721	Swapping Nodes in a Linked List	Medium	SwappingNodesinaLinkedList

Hashtable

No	Question	Level	Solution
1512	Valid Palindrome	Easy	NumberofGoodPairs
771	Jewels and Stones	Easy	JewelAndStones
739	Daily Temperatures	Easy	DailyTemperatures
94	Binary Tree Inorder Traversal	Easy	BinaryTreeInorderTraversal
1	Two Sum	Easy	TwoSum
1207	Unique Number of Occurrences	Easy	UniqueNumberofOccurrences
187	Repeated DNA Sequences	Medium	RepeatedDNASequences

Tree

No	Question	Level	Solution
938	Range Sum of BST	Easy	RangeSumofBST
617	Merge Two Binary Trees	Easy	MergeTwoBinaryTrees
700	Search in a Binary Search Tree	Easy	SearchinaBinarySearchTree
266	Invert Binary Tree	Easy	InvertBinaryTree
589	N-ary Tree Preorder Traversal	Easy	NaryTreePreorderTraversal
145	Binary Tree Postorder Traversal	Medium	BinaryTreePostorderTraversal
897	Increasing Order Search Tree	Easy	IncreasingOrderSearchTree
590	N-ary Tree Postorder Traversal	Easy	NaryTreePostorderTraversal
144	Binary Tree Preorder Traversal	Medium	BinaryTreePreorderTraversal
965	Univalued Binary Tree	Easy	UnivaluedBinaryTree
102	Binary Tree Level Order Traversal	Medium	BinaryTreeLevelOrderTraversal
104	Maximum Depth of Binary Tree	Easy	MaximumDepthofBinaryTree
874	Leaf-Similar Trees	Easy	LeafSimilarTrees
637	Average of Levels in Binary Tree	Easy	AverageofLevelsinBinaryTree
669	Trim a Binary Search Tree	Easy	TrimaBinarySearchTree
538	Convert BST to Greater Tree	Easy	ConvertBSTtoGreaterTree
635	Two Sum IV - Input is a BST	Easy	TwoSumIVInputisaBST
606	Construct String from Binary Tree	Easy	ConstructStringfromBinaryTree
107	Binary Tree Level Order Traversal II	Easy	BinaryTreeLevelOrderTraversalII
100	Same Tree	Easy	SameTree
100	Sum of Left Leaves	Easy	SumofLeftLeaves
993	Cousins in Binary Tree	Easy	CousinsinBinaryTree
257	Binary Tree Paths	Easy	BinaryTreePaths
235	Lowest Common Ancestor of a Binary Search Tree	Easy	LowestCommonAncestorofaBinarySearchTree
563	Binary Tree Tilt	Easy	BinaryTreeTilt
101	Symmetric Tree	Easy	SymmetricTree
572	Subtree of Another Tree	Easy	SubtreeofAnotherTree
1379	Find a Corresponding Node of a Binary Tree in a Clone of That Tree	Easy	ClonedTarget
513	Find Bottom Left Tree Value	Medium	FindBottomLeftTreeValue
108	Convert Sorted Array to Binary Search Tree	Easy	ConvertSortedArraytoBinarySearchTree
1302	Deepest Leaves Sum	Medium	DeepestLeavesSum
1315	Sum of Nodes with Even-Valued Grandparent	Medium	SumofNodeswithEvenValuedGrandparent
671	Second Minimum Node In a Binary Tree	Easy	SecondMaxNodeInaBinaryTree
1161	Maximum Level Sum of a Binary Tree	Easy	MaximumLevelSumofaBinaryTree
111	Minimum Depth of Binary Tree	Easy	MinimumDepthofBinaryTree
559	Maximum Depth of N-ary Tree	Easy	MaximumDepthofNaryTree
112	Path Sum	Easy	PathSum
802	Find Eventual Safe States	Medium	FindEventualSafeStates
701	Insert into a Binary Search Tree	Medium	InsertintoaBinarySearchTree
450	Delete Node in a BST	Medium	DeleteNodeinaBST
1008	Construct Binary Search Tree from Preorder Traversal	Medium	ConstructBinarySearchTreefromPreorderTraversal
103	Binary Tree Zigzag Level Order Traversal	Medium	BinaryTreeZigzagLevelOrderTraversal
199	Binary Tree Right Side View	Medium	BinaryTreeRightSideView
1609	Even Odd Tree	Medium	EvenOddTree
1038	Binary Search Tree to Greater Sum Tree	Medium	BinarySearchTreetoGreaterSumTree
1448	Count Good Nodes in Binary Tree	Medium	CountGoodNodesinBinaryTree
99	Recover Binary Search Tree	Hard	RecoverBinarySearchTree
1026	Maximum Difference Between Node and Ancestor	Medium	MaximumDifferenceBetweenNodeandAncestor
116	Populating Next Right Pointers in Each Node	Medium	PopulatingNextRightPointersinEachNode
230	Kth Smallest Element in a BST	Medium	KthSmallestElementinaBST
1261	Find Elements in a Contaminated Binary Tree	Medium	FindElementsinaContaminatedBinaryTree
1110	Delete Nodes And Return Forest	Medium	DeleteNodesAndReturnForest
113	Path Sum II	Medium	PathSumII
814	Binary Tree Pruning	Medium	BinaryTreePruning
865	Smallest Subtree with all the Deepest Nodes	Medium	SmallestSubtreewithalltheDeepestNodes

Graph

No	Question	Level	Solution
997	Find the Town Judge	Easy	FindtheTownJudge
1042	Flower Planting With No Adjacent	Easy	FlowerPlantingWithNoAdjacent
841	Keys and Rooms	Medium	KeysandRooms
1306	Jump Game III	Medium	JumpGameIII
1267	Count Servers that Communicate	Medium	CountServersthatCommunicate
207	Course Schedule	Medium	CourseSchedule
684	Redundant Connection	Medium	RedundantConnection
332	Reconstruct Itinerary	Medium	ReconstructItinerary
210	Course Schedule II	Medium	CourseScheduleII
1557	Minimum Number of Vertices to Reach All Nodes	Medium	MinimumNumberofVerticestoReachAllNodes
1387	Sort Integers by The Power Value	Medium	SortIntegersbyThePowerValue
785	Is Graph Bipartite?	Medium	IsGraphBipartite
547	Friend Circles	Medium	FriendCircles
547	Friend Circles	Medium	FriendCircles
133	Clone Graph	Medium	CloneGraph
310	Minimum Height Trees	Medium	MinimumHeightTrees

Math

No	Question	Level	Solution
949	Largest Time for Given Digits	Easy	LargestTimeforGivenDigits
7	Reverse Integer	Easy	ReverseInteger
728	Self Dividing Numbers	Easy	SelfDividingNumbers
204	Count Primes	Easy	CountPrimes
799	Champagne Tower	Medium	ChampagneTower
1217	Minimum Cost to Move Chips to The Same Position	Easy	MinimumCosttoMoveChipstoTheSamePosition
593	Valid Square	Medium	ValidSquare
458	Poor Pigs	Medium	PoorPig

Binary Search

No	Question	Level	Solution
704	Binary Search	Easy	BinarySearch
153	Find Minimum in Rotated Sorted Array	Medium	FindMinimuminRotatedSortedArray
33	Search in Rotated Sorted Array	Medium	SearchinRotatedSortedArray
81	Search in Rotated Sorted Array II	Medium	SearchinRotatedSortedArrayII

Sorting

No	Question	Level	Solution
452	Minimum Number of Arrows to Burst Balloons	Medium	MinimumNumberofArrowstoBurstBalloons

Greedy

No	Question	Level	Solution
1007	Minimum Domino Rotations For Equal Row	Medium	MinimumDominoRotationsForEqualRow
392	Is Subsequence	Easy	IsSubsequence
948	Bag of Tokens	Medium	BagofTokens
1094	Car Pooling	Medium	CarPooling
1685	Sum of Absolute Differences in a Sorted Array	Medium	SumofAbsoluteDifferencesinaSortedArray

Dynamic Programming

No	Question	Level	Solution
198	House Robber	Easy	HouseRobber
213	House Robber II	Easy	HouseRobberII
746	Min Cost Climbing Stairs	Easy	MinCostClimbingStairs
70	Climbing Stairs	Easy	ClimbingStairs
121	Best Time to Buy and Sell Stock	Easy	BestTimetoBuyandSellStock
123	Best Time to Buy and Sell Stock III	Hard	BestTimetoBuyandSellStockIII
1510	Stone Game IV	Hard	StoneGameIV
300	Longest Increasing Subsequence	Medium	LongestIncreasingSubsequence
673	Number of Longest Increasing Subsequence	Medium	NumberofLongestIncreasingSubsequence
902	Numbers At Most N Given Digit Set	Hard	NumbersAtMostNGivenDigitSet
902	House Robber III	Medium	HouseRobberIII
1641	Count Sorted Vowel Strings	Medium	CountSortedVowelStrings
416	Partition Equal Subset Sum	Medium	PartitionEqualSubsetSum
62	Unique Paths	Medium	UniquePaths
63	Unique Paths II	Medium	UniquePathsII
70	Climbing Stairs	Easy	ClimbingStairs
1690	Stone Game VII	Medium	Stone Game VII

Backtracking

No	Question	Level	Solution
1242	Iterator for Combination	Medium	IteratorforCombination
47	Permutations II	Medium	PermutationsII

Sliding Windows

No	Question	Level	Solution
395	Longest Substring with At Least K Repeating Character	Medium	LongestSubstringwithAtLeastKRepeatingCharacter
1052	Grumpy Bookstore Owner	Medium	GrumpyBookstoreOwner
3	Longest Substring Without Repeating Characters	Medium	LongestSubstringWithoutRepeatingCharacters
1456	Maximum Number of Vowels in a Substring of Given Length	Medium	MaximumNumberofVowelsinaSubstringofGivenLength
904	Fruit Into Baskets	Medium	FruitIntoBaskets
424	Longest Repeating Character Replacement	Medium	LongestRepeatingCharacterReplacement
76	Minimum Window Substring	Hard	MinimumWindowSubstring
438	Find All Anagrams in a String	Medium	FindAllAnagramsinaString

Breadth First Search

No	Question	Level	Solution
1345	Jump Game IV	Hard	JumpGameIV

Multithreading

No	Question	Level	Solution
1114	Print in Order	Easy	PrintinOrder
1115	Print FooBar Alternately	Medium	PrintFooBarAlternately

Misc

No	Question	Level	Solution
1242	Number of Steps to Reduce a Number to Zero	Easy	NumberofStepstoReduceaNumbertoZero
1365	How Many Numbers Are Smaller Than the Current Number	Easy	HowManyNumbersAreSmallerThantheCurrentNumber
1281	Subtract the Product and Sum of Digits of an Integer	Easy	SubtracttheProductandSumofDigitsofanInteger
1009	Complement of Base 10 Integer	Easy	ComplementofBase10Integer
1603	Design Parking System	Easy	DesignParkingSystem

#Heap

No	Question	Level	Solution
1705	Maximum Number of Eaten Apples	Medium	MaximumNumberofEatenApples
73	K Closest Points to Origin	Medium	KClosestPointstoOrigin
1046	Last Stone Weight	Easy	LastStoneWeight
703	Kth Largest Element in a Stream	Easy	KthLargestElementinaStream

Sql

No	Question	Level	Solution
595	Big Countries	Easy	BigCountries

Bitwise

No	Question	Level	Solution
1720Decode XORed Array	Easy	DecodeXORedArray)