Leetcode

#	Title	Solutions	Difficulty	Tags
0001	Two Sum	Solution	Easy	Hash Table, Array
0002	Add Two Numbers	Solution	Medium	Linked List, Math, Recursion
0003	Longest Substring Without Repeating Characters	Solution	Medium	Hash Table, String, Sliding Window
0005	Longest Palindromic Substring	Solution	Medium	String, Dynamic Programming
0007	Reverse Integer	Solution	Easy	Math
0009	Palindrome Number	Solution	Easy	Math
0011	Container With Most Water	Solution	Medium	Array, Two Pointers, Greedy
0013	Roman to Integer	Solution	Easy	Hash Table, Math, String
0014	Longest Common Prefix	Solution	Easy	String
0015	3Sum	Solution	Medium	Array, Two Pointers, Sorting
0016	3Sum Closest	Solution	Medium	Array, Two Pointers, Sorting
0017	Letter Combinations of a Phone Number	Solution	Medium	Hash Table, String, Backtracking
0018	4Sum	Solution	Medium	Array, Two Pointers, Sorting
0019	Remove Nth Node From End of List	Solution	Medium	Linked List, Two Pointers
0020	Valid Parentheses	Solution	Easy	String, Stack
0021	Merge Two Sorted Lists	Solution	Easy	Linked List, Recursion
0024	Swap Nodes in Pairs	Solution	Medium	Linked List
0025	Reverse Nodes in k-Group	Solution	Hard	Linked List
0026	Remove Duplicates from Sorted Array	Solution	Easy	Array, Two Pointers
0027	Remove Element	Solution	Easy	Array, Two Pointers
0028	Implement strStr()	Solution	Easy	Two Pointers, String, String Matching
0031	Next Permutation	Solution	Medium	Array, Two Pointers
0033	Search in Rotated Sorted Array	Solution	Medium	Binary Search, Array
0034	Find First and Last Position of Element in Sorted Array	Solution	Medium	Binary Search, Array
0035	Search Insert Position	Solution	Easy	Binary Search, Array
0046	Permutations	Solution	Medium	Array, Backtracking
0048	Rotate Image	Solution	Medium	Array, Math, Matrix
0051	N-Queens	Solution	Hard	Array, Backtracking
0052	N-Queens II	Solution	Hard	Array, Backtracking
0054	Spiral Matrix	Solution	Medium	Array, Matrix, Simulation
0055	Jump Game	Solution	Medium	Array, Greedy
0059	Spiral Matrix II	Solution	Medium	Array, Matrix, Simulation
0058	Length of Last Word	Solution	Easy	String
0061	Rotate List	Solution	Medium	LinkedList, Two Pointers
0062	Unique Paths	Solution	Medium	Math, Dynamic Programming
0066	Plus One	Solution	Easy	Array
0067	Add Binary	Solution	Easy	Bit Manipulation, String
0069	Sqrt(x)	Solution	Easy	Binary Search, Math
0070	Climbing Stairs	Solution	Easy	Math, Dynamic Programming, Memoization
0074	Search a 2D Matrix	Solution	Medium	Binary Search, Matrix
0075	Sort Colors	Solution	Medium	Two Pointers, Array
0078	Subsets	Solution	Medium	Array, Backtracking
0080	Remove Duplicates from Sorted Array II	Solution	Medium	Two Pointers, Array
0081	Search in Rotated Sorted Array II	Solution	Medium	Binary Search, Array
0086	Partition List	Solution	Medium	Linked List, Two Pointers
0088	Merge Sorted Array	Solution	Easy	Two Pointers, Array
0090	Subsets II	Solution	Medium	Array, Backtracking
0091	Decode Ways	Solution	Medium	String, Dynamic Programming
0092	Reverse Linked List II	Solution	Medium	Linked List
0094	Binary Tree Inorder Traversal	Solution	Easy	Stack, Tree, Depth-First Search, Binary Tree
0097	Interleaving String	Solution	Medium	String, Dynamic Programming
0098	Validate Binary Search Tree	Solution	Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree
0100	Same Tree	Solution	Easy	Tree, Depth-First Search, Breadth-First Search, Binary Tree
0102	Binary Tree Level Order Traversal	Solution	Easy	Tree, Breadth-First Search, Binary Tree
0103	Binary Tree Zigzag Level Order Traversal	Solution	Medium	Tree, Breadth-First Search, Binary Tree
0104	Maximum Depth of Binary Tree	Solution	Easy	Tree, Depth-First Search, Breadth-First Search, Binary Tree
0105	Construct Binary Tree from Preorder and Inorder Traversal	Solution	Medium	Array, Hash Table, Divide and Conquer, Tree, Binary Tree
0106	Construct Binary Tree from Inorder and Postorder Traversal	Solution	Medium	Array, Hash Table, Divide and Conquer, Tree, Binary Tree
0107	Binary Tree Level Order Traversal II	Solution	Medium	Tree, Breadth-First Search, Binary Tree
0110	Balanced Binary Tree	Solution	Easy	Tree, Depth-First Search, Binary Tree
0111	Minimum Depth of Binary Tree	Solution	Easy	Tree, Depth-First Search, Breadth-First Search, Binary Tree
0112	Path Sum	Solution	Easy	Tree, Depth-First Search, Breadth-First Search, Binary Tree
0113	Path Sum II	Solution	Medium	Backtracking, Tree, Depth-First Search, Binary Tree
0116	Populating Next Right Pointers in Each Node	Solution	Medium	Tree, Depth-First Search, Breadth-First Search, Binary Tree
0117	Populating Next Right Pointers in Each Node II	Solution	Medium	Tree, Depth-First Search, Breadth-First Search, Binary Tree
0118	Pascal's Triangle	Solution	Easy	Array
0118	Pascal's Triangle II	Solution	Easy	Array
0124	Binary Tree Maximum Path Sum	Solution	Hard	Dynamic Programming, Tree, Depth-First Search, Binary Tree
0125	Valid Palindrome	Solution	Easy	Two Pointers, String
0128	Longest Consecutive Sequence	Solution	Medium	Array, Hash Table
0135	Candy	Solution	Hard	Array, Greedy
0136	Single Number	Solution	Easy	Bit Manipulation
0137	Single Number II	Solution	Medium	Bit Manipulation
0141	Linked List Cycle	Solution	Easy	Hash Table, Linked List, Two Pointers
0142	Linked List Cycle II	Solution	Medium	Hash Table, Linked List, Two Pointers
0144	Binary Tree Preorder Traversal	Solution	Easy	Stack, Tree, Depth-First Search, Binary Tree
0145	Binary Tree Postorder Traversal	Solution	Easy	Stack, Tree, Depth-First Search, Binary Tree
0151	Reverse Words in a String	Solution	Medium	String
0153	Find Minimum in Rotated Sorted Array	Solution	Medium	Binary Search, Array
0160	Intersection of Two Linked Lists	Solution	Easy	Hash Table, Linked List, Two Pointers
0162	Find Peak Element	Solution	Medium	Binary Search, Array
0167	Two Sum II - Input array is sorted	Solution	Easy	Two Pointers, Array
0171	Excel Sheet Column Number	Solution	Easy	Math
0173	Binary Search Tree Iterator	Solution	Medium	Stack, Tree, Design, Binary Search Tree, Binary Tree, Iterator
0189	Rotate Array	Solution	Medium	Array, Math, Two Pointers
0191	Number of 1 Bits	Solution	Easy	Bit Manipulation
0199	Binary Tree Right Side View	Solution	Medium	Tree, Depth-First Search, Breadth-First Search, Binary Tree
0203	Remove Linked List Elements	Solution	Easy	Linked List
0205	Isomorphic Strings	Solution	Easy	String, Hash Table
0206	Reverse Linked List	Solution	Easy	Linked List, Recursion
0215	Kth Largest Element in an Array	Solution	Medium	Array, Heap(Priority Queue)
0217	Contains Duplicate	Solution	Easy	Array, Hash Table, Sorting
0219	Contains Duplicate II	Solution	Easy	Array, Hash Table, Sliding Window
0225	Implement Stack using Queues	Solution	Easy	Stack, Design, Queue
0226	Invert Binary Tree	Solution	Easy	Tree, Depth-First Search, Binary Search Tree, Binary Tree
0230	Kth Smallest Element in a BST	Solution	Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree
0231	Power of Two	Solution	Easy	Math, Bit Manipulation, Recursion
0234	Palindrome Linked List	Solution	Easy	Linked List, Two Pointers
0235	Lowest Common Ancestor of a Binary Search Tree	Solution	Easy	Tree, Depth-First Search, Binary Search Tree, Binary Tree
0236	Lowest Common Ancestor of a Binary Tree	Solution	Medium	Tree, Depth-First Search, Binary Tree
0237	Delete Node in a Linked List	Solution	Easy	Linked List
0240	Search a 2D Matrix II	Solution	Medium	Binary Search, Matrix
0242	Valid Anagram	Solution	Easy	Hash Table, String, Sorting
0257	Binary Tree Paths	Solution	Easy	String, Backtracking, Tree, Depth-First Search, Binary Tree
0260	Single Number III	Solution	Medium	Bit Manipulation
0268	Missing Number	Solution	Easy	Array, Math
0284	Peeking Iterator	Solution	Medium	Array Design, Iterator
0289	Game of Life	Solution	Medium	Array, Matrix, Simulation
0303	Range Sum Query - Immutable	Solution	Easy	Array, Design, Prefix Sum
0304	Range Sum Query 2D - Immutable	Solution	Medium	Array, Design, Matrix, Prefix Sum
0344	Reverse String	Solution	Easy	Two Pointers, String
0345	Reverse Vowels of a String	Solution	Easy	Two Pointers, String
0347	Top K Frequent Elements	Solution	Medium	Array, Hash Table, Heap(Priority Queue), Counting
0349	Intersection of Two Arrays	Solution	Easy	Array
0367	Valid Perfect Square	Solution	Easy	Binary Search, Math
0376	Wiggle Subsequence	Solution	Medium	Array, Greedy
0387	First Unique Character in a String	Solution	Easy	String, Hash Table
0406	Queue Reconstruction by Height	Solution	Medium	Array, Greedy, Sorting
0410	Split Array Largest Sum	Solution	Hard	Binary Search, Array, Greedy
0412	Fizz Buzz	Solution	Easy	Math, String
0451	Sort Characters By Frequency	Solution	Medium	Hash Table, String, Heap(Priority Queue), Counting
0454	4Sum II	Solution	Medium	Array, Hash Table
0456	132 Pattern	Solution	Medium	Array, Stack, Monotonic Stack
0461	Hamming Distance	Solution	Easy	Bit Manipulation
0462	Minimum Moves to Equal Array Elements II	Solution	Medium	Array, Math, Sorting
0473	Matchsticks to Square	Solution	Medium	Array, Backtracking
0477	Total Hamming Distance	Solution	Medium	Bit Manipulation
0485	Max Consecutive Ones	Solution	Easy	Array
0496	Next Greater Element I	Solution	Easy	Array, Stack, Hash Table
0500	Keyboard Problem	Solution	Easy	Array, String
0503	Next Greater Element II	Solution	Medium	Array, Stack
0509	Fibonacci Number	Solution	Easy	Math, Dynamic Programming, Recursion, Memoization
0515	Find Largest Value in Each Tree Row	Solution	Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree
0523	Continuous Subarray Sum	Solution	Medium	Array, Hash Table, Math, Prefix Sum
0532	K-diff Pairs in an Array	Solution	Medium	Array, Hash Table
0535	Encode and Decode TinyURL	Solution	Medium	Hash Table, String, Design, Hash Function
0537	Complex Number Multiplication	Solution	Medium	String, Math
0538	Convert BST to Greater Tree	Solution	Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree
0540	Single Element in a Sorted Array	Solution	Medium	Binary Search, Array
0543	Diameter of Binary Tree	Solution	Easy	Tree, Depth-First Search, Binary Tree
0556	Next Greater Element III	Solution	Medium	Math, String
0560	Subarray Sum Equals K	Solution	Medium	Array, Hash Table, Prefix Sum
0576	Out of Boundary Paths	Solution	Medium	Dynamic Programming
0581	Shortest Unsorted Continuous Subarray	Solution	Medium	Array, Two Pointers, Sorting
0662	Maximum Width of Binary Tree	Solution	Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree
0665	Non-decreasing Array	Solution	Medium	Array
0669	Trim a Binary Search Tree	Solution	Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree
0671	Second Minimum Node In a Binary Tree	Solution	Easy	Tree, Depth-First Search, Binary Tree
0680	Valid Palindrome II	Solution	Easy	Two Pointers, String
0682	Baseball Game	Solution	Easy	Array, Stack, Simulation
0693	Binary Number with Alternating Bits	Solution	Easy	Bit Manipulation
0700	Search in a Binary Search Tree	Solution	Easy	Tree, Binary Search Tree, Binary Tree
0703	Kth Largest Element in a Stream	Solution	Easy	Design, Heap(Priority Queue), Data Stream
0704	Binary Search	Solution	Easy	Binary Search
0705	Design HashSet	Solution	Easy	Array, Hash Table, Linked List, Design, Hash Function
0706	Design HashMap	Solution	Easy	Array, Hash Table, Linked List, Design, Hash Function
0709	To Lower Case	Solution	Easy	String
0735	Asteroid Collision	Solution	Medium	Array, Stack
0739	Daily Temperatures	Solution	Medium	Array, Stack
0744	Find Smallest Letter Greater Than Target	Solution	Easy	Binary Search, Array
0746	Min Cost Climbing Stairs	Solution	Easy	Array, Dynamic Programming
0771	Jewels and Stones	Solution	Easy	String, Hash Table
0784	Letter Case Permutation	Solution	Medium	String, Backtracking
0844	Backspace String Compare	Solution	Easy	String, Stack, Simulation
0852	Peak Index in a Mountain Array	Solution	Easy	Binary Search, Array
0867	Transpose Matrix	Solution	Easy	Array, Matrix, Simulation
0876	Middle of the Linked List	Solution	Easy	Linked List, Two Pointers
0890	Find and Replace Pattern	Solution	Medium	String, Hash Table
0905	Sort Array By Parity	Solution	Easy	Array, Two Pointers, Sorting
0921	Minimum Add to Make Parentheses Valid	Solution	Medium	String
0923	3Sum With Multiplicity	Solution	Medium	Array, Hash Table, Two Pointers, Counting, Sorting
0929	Unique Email Address	Solution	Easy	String
0917	Reverse Only Letters	Solution	Easy	Two Pointers, String
0977	Squares of a Sorted Array	Solution	Easy	Two Pointers, Array
1011	Capacity To Ship Packages Within D Days	Solution	Medium	Binary Search, Array, Greedy
1022	Sum of Root To Leaf Binary Numbers	Solution	Easy	Tree, Depth-First Search, Binary Tree
1038	Binary Search Tree to Greater Sum Tree	Solution	Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree
1041	Robot Bounded in Circle	Solution	Medium	String, Math
1046	Last Stone Weight	Solution	Easy	Array, Heap(Priority Queue)
1047	Remove All Adjacent Duplicates In String	Solution	Easy	String, Stack
1074	Number of Submatrices That Sum to Target	Solution	Hard	Array, Hash Table, Matrix, Prefix Sum
1108	Defanging an IP Address	Solution	Easy	String
1121	Split a String in Balanced Strings	Solution	Easy	String
1209	Remove All Adjacent Duplicates in String II	Solution	Medium	String, Stack
1260	Shift 2D Grid	Solution	Easy	Array, Matrix, Simulation
1281	Subtract the Product and Sum of Digits of an Integer	Solution	Easy	Math
1283	Find the Smallest Divisor Given a Threshold	Solution	Medium	Binary Search, Array
1299	Replace Elements with Greatest Element on Right Side	Solution	Easy	Array
1302	Deepest Leaves Sum	Solution	Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree
1332	Remove Palindromic Subsequences	Solution	Easy	Two Pointers, String
1347	Minimum number od Steps to make two Strings Anagrams	Solution	Medium	String
1354	Construct Target Array With Multiple Sums	Solution	Medium	Array, Heap(Priority Queue)
1365	How Many Numbers Are Smaller Than the Current Number	Solution	Easy	Array
1379	Find a Corresponding Node of a Binary Tree in a Clone of That Tree	Solution	Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree
1396	Design Underground System	Solution	Medium	Hash Table, String, Design
1423	Maximum Points You Can Obtain from Cards	Solution	Medium	Array, Sliding Window, Prefix Sum
1431	Kids With the Greatest Number of Candies	Solution	Easy	Array
1461	Check If a String Contains All Binary Codes of Size K	Solution	Medium	Hash Table, String
1465	Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts	Solution	Medium	Array, Greedy, Sorting
1470	Shuffle the Array	Solution	Easy	Array
1480	Running Sum of 1d Array	Solution	Easy	Array, Prefix Sum
1486	XOR Operation in an Array	Solution	Easy	Array
1512	Number of Good Pairs	Solution	Easy	Array
1518	Water Bottles	Solution	Easy	Array
1528	Shuffle String	Solution	Easy	String
1589	Crawler Log Folder	Solution	Easy	Array, String, Stack
1614	Maximum Nesting Depth of the Parentheses	Solution	Easy	String
1636	Sort Array by Increasing Frequency	Solution	Easy	Array, Hash Table, Sorting
1642	Furthest Building You Can Reach	Solution	Medium	Array, Greedy, Heap(Priority Queue)
1647	Minimum Deletions to Make Character Frequencies Unique	Solution	Medium	String, Greedy, Sorting
1662	Check If Two String Arrays are Equivalent	Solution	Easy	Array, String
1672	Richest Customer Wealth	Solution	Easy	Array
1678	Goal Parser Interpretation	Solution	Easy	String
1679	Max Number of K-Sum Pairs	Solution	Medium	Array, Hash Table, Two Pointers, Sorting
1684	Count the Number of Consistent Strings	Solution	Easy	String
1689	Partitioning Into Minimum Number Of Deci-Binary Numbers	Solution	Medium	String, Greedy
1695	Maximum Erasure Value	Solution	Medium	Array, Hash Table, Sliding Window
1696	Jump Game VI	Solution	Medium	Array, Dynamic Programming, Queue, Sliding Window, Heap(Priority Queue), Monotonic Queue
1710	Maximum Units on a Truck	Solution	Easy	Array, Greedy, Sorting
1721	Swapping Nodes in a Linked List	Solution	Medium	Linked List, Two Pointers
1773	Count Items Matching a Rule	Solution	Easy	String
1816	Truncate Sentence	Solution	Easy	String
1832	Check if the Sentence is Pangram	Solution	Easy	String, Hash Table
1859	Sorting the sentence	Solution	Easy	String
1880	Check if Word Equals Summation of Two Words	Solution	Easy	String
1886	Determine Whether Matrix Can Be Obtained By Rotation	Solution	Easy	Array, Matrix
1925	Count Square Sum Triples	Solution	Easy	Math
1985	Find the Kth Largest Integer in the Array	Solution	Medium	Array, String, Heap(Priority Queue)
2099	Find Subsequence of Length K With the Largest Sum	Solution	Easy	Array, Hash Table, Sorting, Heap(Priority Queue)
2108	Find First Palindromic String in the Array	Solution	Easy	Array, Two Pointers, String
2177	Find Three Consecutive Integers That Sum to a Given Number	Solution	Medium	Math, Simulation
2233	Maximum Product After K Increments	Solution	Medium	Array, Greedy, Heap(Priority Queue)
2279	Maximum Bags With Full Capacity of Rocks	Solution	Medium	Array, Greedy, Sorting