LeetCode

LeetCode fuss 👀

Problem	Solution	Topics	Difficulty
1. Two Sum	😎	Array Hash Table
2. Add Two Numbers	🤔	Linked List Math Recursion
3. Longest Substring Without Repeating Characters	🤔	Hash Table String Sliding Window
5. Longest Palindromic Substring	🤔	Two Pointers String Dynamic Programming
17. Letter Combinations of a Phone Number	🤔	Hash Table String Backtracking
19. Remove Nth Node From End of List	🤔	Linked List Two Pointers
20. Valid Parentheses	😎	String Stack
21. Merge Two Sorted Lists	😎	Linked List Recursion
22. Generate Parentheses	🤔	String Dynamic Programming Backtracking
23. Merge k Sorted Lists	😤	Linked List Divide and Conquer Heap (Priority Queue) Merge Sort
24. Swap Nodes in Pairs	🤔	Linked List Recursion
26. Remove Duplicates from Sorted Array	😎	Array Two Pointers
33. Search in Rotated Sorted Array	🤔	Array Binary Search
42. Trapping Rain Water	😤	Array Two Pointers Dynamic Programming Stack Monotonic Stack
48. Rotate Image	🤔	Array Math Matrix
49. Group Anagrams	🤔	Array Hash Table String Sorting
56. Merge Intervals	🤔	Array Sorting
66. Plus One	😎	Array Math
71. Simplify Path	🤔	String Stack
88. Merge Sorted Array	😎	Array Two Pointers Sorting
98. Validate Binary Search Tree	🤔	Tree Depth-First Search Binary Search Tree Binary Tree
101. Symmetric Tree	😎	Tree Depth-First Search Breadth-First Search Binary Tree
102. Binary Tree Level Order Traversal	🤔	Tree Breadth-First Search Binary Tree
103. Binary Tree Zigzag Level Order Traversal	🤔	Tree Breadth-First Search Binary Tree
125. Valid Palindrome	😎	Two Pointers String
136. Single Number	😎	Array Bit Manipulation
146. LRU Cache	🤔	Hash Table Linked List Design Doubly-Linked List
150. Evaluate Reverse Polish Notation	🤔	Array Math Stack
153. Find Minimum in Rotated Sorted Array	🤔	Array Binary Search
159. Longest Substring with At Most Two Distinct Characters	🤔	Hash Table String Sliding Window
161. One Edit Distance	🤔	Two Pointers String
167. Two Sum II - Input Array Is Sorted	🤔	Array Two Pointers Binary Search
199. Binary Tree Right Side View	🤔	Tree Depth-First Search Breadth-First Search Binary Tree
200. Number of Islands	🤔	Array Depth-First Search Breadth-First Search Union Find Matrix
204. Count Primes	🤔	Array Math Enumeration Number Theory
206. Reverse Linked List	😎	Linked List Recursion
228. Summary Ranges	😎	Array
232. Implement Queue using Stacks	😎	Stack Design Queue
234. Palindrome Linked List	😎	Linked List Two Pointers Stack Recursion
236. Lowest Common Ancestor of a Binary Tree	🤔	Tree Depth-First Search Binary Tree
238. Product of Array Except Self	🤔	Array Prefix Sum
253. Meeting Rooms II	🤔	Greedy Array Two Pointers Prefix Sum Sorting Heap (Priority Queue)
268. Missing Number	😎	Array Hash Table Math Binary Search Bit Manipulation Sorting
279. Perfect Squares	🤔	Math Dynamic Programming Breadth-First Search
281. Zigzag Iterator	🤔	Design Queue Array Iterator
283. Move Zeroes	😎	Array Two Pointers
300. Longest Increasing Subsequence	🤔	Array Binary Search Dynamic Programming
341. Flatten Nested List Iterator	🤔	Stack Tree Depth-First Search Design Queue Iterator
350. Intersection of Two Arrays II	😎	Array Hash Table Two Pointers Binary Search Sorting
356. Line Reflection	🤔	Array Hash Table Math
362. Design Hit Counter	🤔	Design Queue Array Binary Search
380. Insert Delete GetRandom O(1)	🤔	Array Hash Table Math Design Randomized
387. First Unique Character in a String	😎	Hash Table String Queue Counting
392. Is Subsequence	😎	Two Pointers String Dynamic Programming
415. Add Strings	😎	Math String Simulation
424. Longest Repeating Character Replacement	🤔	Hash Table String Sliding Window
438. Find All Anagrams in a String	🤔	Hash Table String Sliding Window
443. String Compression	🤔	Two Pointers String
448. Find All Numbers Disappeared in an Array	😎	Array Hash Table
470. Implement Rand10() Using Rand7()	🤔	Math Rejection Sampling Randomized Probability and Statistics
487. Max Consecutive Ones II	🤔	Array Dynamic Programming Sliding Window
523. Continuous Subarray Sum	🤔	Array Hash Table Math Prefix Sum
557. Reverse Words in a String III	😎	Two Pointers String
560. Subarray Sum Equals K	🤔	Array Hash Table Prefix Sum
567. Permutation in String	🤔	Hash Table Two Pointers String Sliding Window
658. Find K Closest Elements	🤔	Array Two Pointers Binary Search Sliding Window Sorting Heap (Priority Queue)
712. Minimum ASCII Delete Sum for Two Strings	🤔	String Dynamic Programming
716. Max Stack	😎	Stack Design Linked List Doubly-Linked List Ordered Set
763. Partition Labels	🤔	Hash Table Two Pointers String Greedy
771. Jewels and Stones	😎	Hash Table String
849. Maximize Distance to Closest Person	🤔	Array
933. Number of Recent Calls	😎	Design Queue Data Stream
938. Range Sum of BST	😎	Tree Depth-First Search Binary Search Tree Binary Tree
961. N-Repeated Element in Size 2N Array	😎	Array Hash Table
977. Squares of a Sorted Array	😎	Array Two Pointers Sorting
986. Interval List Intersections	🤔	Array Two Pointers Line Sweep
1004. Max Consecutive Ones III	🤔	Array Binary Search Sliding Window Prefix Sum
1161. Maximum Level Sum of a Binary Tree	🤔	Tree Depth-First Search Breadth-First Search Binary Tree
1266. Minimum Time Visiting All Points	😎	Array Math Geometry
1339. Maximum Product of Splitted Binary Tree	🤔	Tree Depth-First Search Binary Tree
1390. Four Divisors	🤔	Array Math
1411. Number of Ways to Paint N × 3 Grid	😤	Dynamic Programming
1446. Consecutive Characters	😎	String
1493. Longest Subarray of 1's After Deleting One Element	🤔	Array Dynamic Programming Sliding Window
1650. Lowest Common Ancestor of a Binary Tree III	🤔	Tree Hash Table Two Pointers Binary Tree
1975. Maximum Matrix Sum	🤔	Array Greedy Matrix

SQL

Using PostgreSQL

Problem	Solution	Topics
SQL Tasks	🛢️	Database