list-03

Question	Free?	Status	Difficulty	Topics	Similar Questions
201. Bitwise AND of Numbers Range  🔗  📝	🆓	✅	⭐️⭐️	Bit Manipulation  🔗
202. Happy Number  🔗  📝	🆓	✅	⭐️	Hash Table  🔗 Math  🔗 Two Pointers  🔗	141. Linked List Cycle  🔗  📝 258. Add Digits  🔗  📝 263. Ugly Number  🔗  📝 1945. Sum of Digits of String After Convert  🔗  📝
203. Remove Linked List Elements  🔗  📝	🆓	✅	⭐️	Linked List  🔗 Recursion  🔗	27. Remove Element  🔗  📝 237. Delete Node in a Linked List  🔗  📝 2095. Delete the Middle Node of a Linked List  🔗  📝
204. Count Primes  🔗  📝	🆓		⭐️⭐️	Array  🔗 Math  🔗 Enumeration  🔗 Number Theory  🔗	263. Ugly Number  🔗  📝 264. Ugly Number II  🔗  📝 279. Perfect Squares  🔗  📝
205. Isomorphic Strings  🔗  📝	🆓	✅	⭐️	Hash Table  🔗 String  🔗	290. Word Pattern  🔗  📝
206. Reverse Linked List  🔗  📝	🆓	✅	⭐️	Linked List  🔗 Recursion  🔗	92. Reverse Linked List II  🔗  📝 156. Binary Tree Upside Down  🔗  📝 234. Palindrome Linked List  🔗  📝 2074. Reverse Nodes in Even Length Groups  🔗  📝 2130. Maximum Twin Sum of a Linked List  🔗  📝
207. Course Schedule  🔗  📝	🆓	✅	⭐️⭐️	Depth-First Search  🔗 Breadth-First Search  🔗 Graph  🔗 Topological Sort  🔗	210. Course Schedule II  🔗  📝 261. Graph Valid Tree  🔗  📝 310. Minimum Height Trees  🔗  📝 630. Course Schedule III  🔗  📝
208. Implement Trie (Prefix Tree)  🔗  📝	🆓	✅	⭐️⭐️	Hash Table  🔗 String  🔗 Design  🔗 Trie  🔗	211. Design Add and Search Words Data Structure  🔗  📝 642. Design Search Autocomplete System  🔗  📝 648. Replace Words  🔗  📝 676. Implement Magic Dictionary  🔗  📝 1804. Implement Trie II (Prefix Tree)  🔗  📝 2227. Encrypt and Decrypt Strings  🔗  📝
209. Minimum Size Subarray Sum  🔗  📝	🆓		⭐️⭐️	Array  🔗 Binary Search  🔗 Sliding Window  🔗 Prefix Sum  🔗	76. Minimum Window Substring  🔗  📝 325. Maximum Size Subarray Sum Equals k  🔗  📝 718. Maximum Length of Repeated Subarray  🔗  📝 1658. Minimum Operations to Reduce X to Zero  🔗  📝 2090. K Radius Subarray Averages  🔗  📝 2233. Maximum Product After K Increments  🔗  📝
210. Course Schedule II  🔗  📝	🆓	✅	⭐️⭐️	Depth-First Search  🔗 Breadth-First Search  🔗 Graph  🔗 Topological Sort  🔗	207. Course Schedule  🔗  📝 269. Alien Dictionary  🔗  📝 310. Minimum Height Trees  🔗  📝 444. Sequence Reconstruction  🔗  📝 630. Course Schedule III  🔗  📝 1136. Parallel Courses  🔗  📝 2115. Find All Possible Recipes from Given Supplies  🔗  📝
211. Design Add and Search Words Data Structure  🔗  📝	🆓	✅	⭐️⭐️	String  🔗 Depth-First Search  🔗 Design  🔗 Trie  🔗	208. Implement Trie (Prefix Tree)  🔗  📝 745. Prefix and Suffix Search  🔗  📝 2301. Match Substring After Replacement  🔗  📝
212. Word Search II  🔗  📝	🆓		⭐️⭐️⭐️	Array  🔗 String  🔗 Backtracking  🔗 Trie  🔗 Matrix  🔗	79. Word Search  🔗  📝 980. Unique Paths III  🔗  📝 2227. Encrypt and Decrypt Strings  🔗  📝
213. House Robber II  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Dynamic Programming  🔗	198. House Robber  🔗  📝 256. Paint House  🔗  📝 276. Paint Fence  🔗  📝 337. House Robber III  🔗  📝 600. Non-negative Integers without Consecutive Ones  🔗  📝 656. Coin Path  🔗  📝
214. Shortest Palindrome  🔗  📝	🆓		⭐️⭐️⭐️	String  🔗 Rolling Hash  🔗 String Matching  🔗 Hash Function  🔗	5. Longest Palindromic Substring  🔗  📝 28. Implement strStr()  🔗  📝 336. Palindrome Pairs  🔗  📝
215. Kth Largest Element in an Array  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Divide and Conquer  🔗 Sorting  🔗 Heap (Priority Queue)  🔗 Quickselect  🔗	324. Wiggle Sort II  🔗  📝 347. Top K Frequent Elements  🔗  📝 414. Third Maximum Number  🔗  📝 703. Kth Largest Element in a Stream  🔗  📝 973. K Closest Points to Origin  🔗  📝 1985. Find the Kth Largest Integer in the Array  🔗  📝 2099. Find Subsequence of Length K With the Largest Sum  🔗  📝 2146. K Highest Ranked Items Within a Price Range  🔗  📝
216. Combination Sum III  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Backtracking  🔗	39. Combination Sum  🔗  📝
217. Contains Duplicate  🔗  📝	🆓	✅	⭐️	Array  🔗 Hash Table  🔗 Sorting  🔗	219. Contains Duplicate II  🔗  📝 220. Contains Duplicate III  🔗  📝 2357. Make Array Zero by Subtracting Equal Amounts  🔗  📝
218. The Skyline Problem  🔗  📝	🆓		⭐️⭐️⭐️	Array  🔗 Divide and Conquer  🔗 Binary Indexed Tree  🔗 Segment Tree  🔗 Line Sweep  🔗 Heap (Priority Queue)  🔗 Ordered Set  🔗	699. Falling Squares  🔗  📝
219. Contains Duplicate II  🔗  📝	🆓	✅	⭐️	Array  🔗 Hash Table  🔗 Sliding Window  🔗	217. Contains Duplicate  🔗  📝 220. Contains Duplicate III  🔗  📝
220. Contains Duplicate III  🔗  📝	🆓		⭐️⭐️	Array  🔗 Sliding Window  🔗 Sorting  🔗 Bucket Sort  🔗 Ordered Set  🔗	217. Contains Duplicate  🔗  📝 219. Contains Duplicate II  🔗  📝
221. Maximal Square  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Dynamic Programming  🔗 Matrix  🔗	85. Maximal Rectangle  🔗  📝 764. Largest Plus Sign  🔗  📝 2132. Stamping the Grid  🔗  📝 2201. Count Artifacts That Can Be Extracted  🔗  📝
222. Count Complete Tree Nodes  🔗  📝	🆓	✅	⭐️⭐️	Binary Search  🔗 Tree  🔗 Depth-First Search  🔗 Binary Tree  🔗	270. Closest Binary Search Tree Value  🔗  📝
223. Rectangle Area  🔗  📝	🆓		⭐️⭐️	Math  🔗 Geometry  🔗	836. Rectangle Overlap  🔗  📝
224. Basic Calculator  🔗  📝	🆓		⭐️⭐️⭐️	Math  🔗 String  🔗 Stack  🔗 Recursion  🔗	150. Evaluate Reverse Polish Notation  🔗  📝 227. Basic Calculator II  🔗  📝 241. Different Ways to Add Parentheses  🔗  📝 282. Expression Add Operators  🔗  📝 772. Basic Calculator III  🔗  📝 2019. The Score of Students Solving Math Expression  🔗  📝 2232. Minimize Result by Adding Parentheses to Expression  🔗  📝
225. Implement Stack using Queues  🔗  📝	🆓		⭐️	Stack  🔗 Design  🔗 Queue  🔗	232. Implement Queue using Stacks  🔗  📝
226. Invert Binary Tree  🔗  📝	🆓	✅	⭐️	Tree  🔗 Depth-First Search  🔗 Breadth-First Search  🔗 Binary Tree  🔗
227. Basic Calculator II  🔗  📝	🆓		⭐️⭐️	Math  🔗 String  🔗 Stack  🔗	224. Basic Calculator  🔗  📝 282. Expression Add Operators  🔗  📝 772. Basic Calculator III  🔗  📝
228. Summary Ranges  🔗  📝	🆓	✅	⭐️	Array  🔗	163. Missing Ranges  🔗  📝 352. Data Stream as Disjoint Intervals  🔗  📝
229. Majority Element II  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Hash Table  🔗 Sorting  🔗 Counting  🔗	169. Majority Element  🔗  📝 1150. Check If a Number Is Majority Element in a Sorted Array  🔗  📝
230. Kth Smallest Element in a BST  🔗  📝	🆓	✅	⭐️⭐️	Tree  🔗 Depth-First Search  🔗 Binary Search Tree  🔗 Binary Tree  🔗	94. Binary Tree Inorder Traversal  🔗  📝 671. Second Minimum Node In a Binary Tree  🔗  📝
231. Power of Two  🔗  📝	🆓	✅	⭐️	Math  🔗 Bit Manipulation  🔗 Recursion  🔗	191. Number of 1 Bits  🔗  📝 326. Power of Three  🔗  📝 342. Power of Four  🔗  📝
232. Implement Queue using Stacks  🔗  📝	🆓		⭐️	Stack  🔗 Design  🔗 Queue  🔗	225. Implement Stack using Queues  🔗  📝
233. Number of Digit One  🔗  📝	🆓	👀	⭐️⭐️⭐️	Math  🔗 Dynamic Programming  🔗 Recursion  🔗	172. Factorial Trailing Zeroes  🔗  📝 1067. Digit Count in Range  🔗  📝
234. Palindrome Linked List  🔗  📝	🆓	✅	⭐️	Linked List  🔗 Two Pointers  🔗 Stack  🔗 Recursion  🔗	9. Palindrome Number  🔗  📝 125. Valid Palindrome  🔗  📝 206. Reverse Linked List  🔗  📝 2130. Maximum Twin Sum of a Linked List  🔗  📝
235. Lowest Common Ancestor of a Binary Search Tree  🔗  📝	🆓	✅	⭐️	Tree  🔗 Depth-First Search  🔗 Binary Search Tree  🔗 Binary Tree  🔗	236. Lowest Common Ancestor of a Binary Tree  🔗  📝 1257. Smallest Common Region  🔗  📝 1644. Lowest Common Ancestor of a Binary Tree II  🔗  📝 1650. Lowest Common Ancestor of a Binary Tree III  🔗  📝 1676. Lowest Common Ancestor of a Binary Tree IV  🔗  📝
236. Lowest Common Ancestor of a Binary Tree  🔗  📝	🆓	✅	⭐️⭐️	Tree  🔗 Depth-First Search  🔗 Binary Tree  🔗	235. Lowest Common Ancestor of a Binary Search Tree  🔗  📝 1257. Smallest Common Region  🔗  📝 1644. Lowest Common Ancestor of a Binary Tree II  🔗  📝 1650. Lowest Common Ancestor of a Binary Tree III  🔗  📝 1676. Lowest Common Ancestor of a Binary Tree IV  🔗  📝 2096. Step-By-Step Directions From a Binary Tree Node to Another  🔗  📝 2225. Find Players With Zero or One Losses  🔗  📝
237. Delete Node in a Linked List  🔗  📝	🆓	✅	⭐️	Linked List  🔗	203. Remove Linked List Elements  🔗  📝
238. Product of Array Except Self  🔗  📝	🆓		⭐️⭐️	Array  🔗 Prefix Sum  🔗	42. Trapping Rain Water  🔗  📝 152. Maximum Product Subarray  🔗  📝 265. Paint House II  🔗  📝 2163. Minimum Difference in Sums After Removal of Elements  🔗  📝
239. Sliding Window Maximum  🔗  📝	🆓	👀	⭐️⭐️⭐️	Array  🔗 Queue  🔗 Sliding Window  🔗 Heap (Priority Queue)  🔗 Monotonic Queue  🔗	76. Minimum Window Substring  🔗  📝 155. Min Stack  🔗  📝 159. Longest Substring with At Most Two Distinct Characters  🔗  📝 265. Paint House II  🔗  📝 1696. Jump Game VI  🔗  📝
240. Search a 2D Matrix II  🔗  📝	🆓		⭐️⭐️	Array  🔗 Binary Search  🔗 Divide and Conquer  🔗 Matrix  🔗	74. Search a 2D Matrix  🔗  📝
241. Different Ways to Add Parentheses  🔗  📝	🆓		⭐️⭐️	Math  🔗 String  🔗 Dynamic Programming  🔗 Recursion  🔗 Memoization  🔗	95. Unique Binary Search Trees II  🔗  📝 224. Basic Calculator  🔗  📝 282. Expression Add Operators  🔗  📝 2019. The Score of Students Solving Math Expression  🔗  📝 2232. Minimize Result by Adding Parentheses to Expression  🔗  📝
242. Valid Anagram  🔗  📝	🆓	✅	⭐️	Hash Table  🔗 String  🔗 Sorting  🔗	49. Group Anagrams  🔗  📝 266. Palindrome Permutation  🔗  📝 438. Find All Anagrams in a String  🔗  📝 2273. Find Resultant Array After Removing Anagrams  🔗  📝
243. Shortest Word Distance  🔗  📝	💰		⭐️	Array  🔗 String  🔗	244. Shortest Word Distance II  🔗  📝 245. Shortest Word Distance III  🔗  📝 2200. Find All K-Distant Indices in an Array  🔗  📝
244. Shortest Word Distance II  🔗  📝	💰		⭐️⭐️	Array  🔗 Hash Table  🔗 Two Pointers  🔗 String  🔗 Design  🔗	21. Merge Two Sorted Lists  🔗  📝 243. Shortest Word Distance  🔗  📝 245. Shortest Word Distance III  🔗  📝
245. Shortest Word Distance III  🔗  📝	💰		⭐️⭐️	Array  🔗 String  🔗	243. Shortest Word Distance  🔗  📝 244. Shortest Word Distance II  🔗  📝
246. Strobogrammatic Number  🔗  📝	💰		⭐️	Hash Table  🔗 Two Pointers  🔗 String  🔗	247. Strobogrammatic Number II  🔗  📝 248. Strobogrammatic Number III  🔗  📝 1056. Confusing Number  🔗  📝
247. Strobogrammatic Number II  🔗  📝	💰		⭐️⭐️	Array  🔗 String  🔗 Recursion  🔗	246. Strobogrammatic Number  🔗  📝 248. Strobogrammatic Number III  🔗  📝 2081. Sum of k-Mirror Numbers  🔗  📝
248. Strobogrammatic Number III  🔗  📝	💰		⭐️⭐️⭐️	Array  🔗 String  🔗 Recursion  🔗	246. Strobogrammatic Number  🔗  📝 247. Strobogrammatic Number II  🔗  📝
249. Group Shifted Strings  🔗  📝	💰		⭐️⭐️	Array  🔗 Hash Table  🔗 String  🔗	49. Group Anagrams  🔗  📝
250. Count Univalue Subtrees  🔗  📝	💰		⭐️⭐️	Tree  🔗 Depth-First Search  🔗 Binary Tree  🔗	572. Subtree of Another Tree  🔗  📝 687. Longest Univalue Path  🔗  📝
251. Flatten 2D Vector  🔗  📝	💰		⭐️⭐️	Array  🔗 Two Pointers  🔗 Design  🔗 Iterator  🔗	173. Binary Search Tree Iterator  🔗  📝 281. Zigzag Iterator  🔗  📝 284. Peeking Iterator  🔗  📝 341. Flatten Nested List Iterator  🔗  📝
252. Meeting Rooms  🔗  📝	💰		⭐️	Array  🔗 Sorting  🔗	56. Merge Intervals  🔗  📝 253. Meeting Rooms II  🔗  📝
253. Meeting Rooms II  🔗  📝	💰		⭐️⭐️	Array  🔗 Two Pointers  🔗 Greedy  🔗 Sorting  🔗 Heap (Priority Queue)  🔗	56. Merge Intervals  🔗  📝 252. Meeting Rooms  🔗  📝 452. Minimum Number of Arrows to Burst Balloons  🔗  📝 1094. Car Pooling  🔗  📝 2251. Number of Flowers in Full Bloom  🔗  📝
254. Factor Combinations  🔗  📝	💰		⭐️⭐️	Array  🔗 Backtracking  🔗	39. Combination Sum  🔗  📝
255. Verify Preorder Sequence in Binary Search Tree  🔗  📝	💰		⭐️⭐️	Stack  🔗 Tree  🔗 Binary Search Tree  🔗 Recursion  🔗 Monotonic Stack  🔗 Binary Tree  🔗	144. Binary Tree Preorder Traversal  🔗  📝
256. Paint House  🔗  📝	💰		⭐️⭐️	Array  🔗 Dynamic Programming  🔗	198. House Robber  🔗  📝 213. House Robber II  🔗  📝 265. Paint House II  🔗  📝 276. Paint Fence  🔗  📝 2304. Minimum Path Cost in a Grid  🔗  📝
257. Binary Tree Paths  🔗  📝	🆓	✅	⭐️	String  🔗 Backtracking  🔗 Tree  🔗 Depth-First Search  🔗 Binary Tree  🔗	113. Path Sum II  🔗  📝 988. Smallest String Starting From Leaf  🔗  📝 2096. Step-By-Step Directions From a Binary Tree Node to Another  🔗  📝
258. Add Digits  🔗  📝	🆓	✅	⭐️	Math  🔗 Simulation  🔗 Number Theory  🔗	202. Happy Number  🔗  📝 1085. Sum of Digits in the Minimum Number  🔗  📝 1945. Sum of Digits of String After Convert  🔗  📝 2160. Minimum Sum of Four Digit Number After Splitting Digits  🔗  📝 2243. Calculate Digit Sum of a String  🔗  📝
259. 3Sum Smaller  🔗  📝	💰		⭐️⭐️	Array  🔗 Two Pointers  🔗 Binary Search  🔗 Sorting  🔗	15. 3Sum  🔗  📝 16. 3Sum Closest  🔗  📝 611. Valid Triangle Number  🔗  📝 1099. Two Sum Less Than K  🔗  📝
260. Single Number III  🔗  📝	🆓		⭐️⭐️	Array  🔗 Bit Manipulation  🔗	136. Single Number  🔗  📝 137. Single Number II  🔗  📝
261. Graph Valid Tree  🔗  📝	💰		⭐️⭐️	Depth-First Search  🔗 Breadth-First Search  🔗 Union Find  🔗 Graph  🔗	207. Course Schedule  🔗  📝 323. Number of Connected Components in an Undirected Graph  🔗  📝 841. Keys and Rooms  🔗  📝
262. Trips and Users  🔗  📝	🆓		⭐️⭐️⭐️	Database  🔗	1635. Hopper Company Queries I  🔗  📝 1645. Hopper Company Queries II  🔗  📝 1651. Hopper Company Queries III  🔗  📝
263. Ugly Number  🔗  📝	🆓	✅	⭐️	Math  🔗	202. Happy Number  🔗  📝 204. Count Primes  🔗  📝 264. Ugly Number II  🔗  📝
264. Ugly Number II  🔗  📝	🆓	✅	⭐️⭐️	Hash Table  🔗 Math  🔗 Dynamic Programming  🔗 Heap (Priority Queue)  🔗	23. Merge k Sorted Lists  🔗  📝 204. Count Primes  🔗  📝 263. Ugly Number  🔗  📝 279. Perfect Squares  🔗  📝 313. Super Ugly Number  🔗  📝 1201. Ugly Number III  🔗  📝
265. Paint House II  🔗  📝	💰		⭐️⭐️⭐️	Array  🔗 Dynamic Programming  🔗	238. Product of Array Except Self  🔗  📝 239. Sliding Window Maximum  🔗  📝 256. Paint House  🔗  📝 276. Paint Fence  🔗  📝
266. Palindrome Permutation  🔗  📝	💰		⭐️	Hash Table  🔗 String  🔗 Bit Manipulation  🔗	5. Longest Palindromic Substring  🔗  📝 242. Valid Anagram  🔗  📝 267. Palindrome Permutation II  🔗  📝 409. Longest Palindrome  🔗  📝
267. Palindrome Permutation II  🔗  📝	💰		⭐️⭐️	Hash Table  🔗 String  🔗 Backtracking  🔗	31. Next Permutation  🔗  📝 47. Permutations II  🔗  📝 266. Palindrome Permutation  🔗  📝
268. Missing Number  🔗  📝	🆓	✅	⭐️	Array  🔗 Hash Table  🔗 Math  🔗 Binary Search  🔗 Bit Manipulation  🔗 Sorting  🔗	41. First Missing Positive  🔗  📝 136. Single Number  🔗  📝 287. Find the Duplicate Number  🔗  📝 765. Couples Holding Hands  🔗  📝 1980. Find Unique Binary String  🔗  📝
269. Alien Dictionary  🔗  📝	💰		⭐️⭐️⭐️	Array  🔗 String  🔗 Depth-First Search  🔗 Breadth-First Search  🔗 Graph  🔗 Topological Sort  🔗	210. Course Schedule II  🔗  📝
270. Closest Binary Search Tree Value  🔗  📝	💰		⭐️	Binary Search  🔗 Tree  🔗 Depth-First Search  🔗 Binary Search Tree  🔗 Binary Tree  🔗	222. Count Complete Tree Nodes  🔗  📝 272. Closest Binary Search Tree Value II  🔗  📝 700. Search in a Binary Search Tree  🔗  📝
271. Encode and Decode Strings  🔗  📝	💰		⭐️⭐️	Array  🔗 String  🔗 Design  🔗	38. Count and Say  🔗  📝 297. Serialize and Deserialize Binary Tree  🔗  📝 443. String Compression  🔗  📝 696. Count Binary Substrings  🔗  📝
272. Closest Binary Search Tree Value II  🔗  📝	💰		⭐️⭐️⭐️	Two Pointers  🔗 Stack  🔗 Tree  🔗 Depth-First Search  🔗 Binary Search Tree  🔗 Heap (Priority Queue)  🔗 Binary Tree  🔗	94. Binary Tree Inorder Traversal  🔗  📝 270. Closest Binary Search Tree Value  🔗  📝
273. Integer to English Words  🔗  📝	🆓		⭐️⭐️⭐️	Math  🔗 String  🔗 Recursion  🔗	12. Integer to Roman  🔗  📝
274. H-Index  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Sorting  🔗 Counting Sort  🔗	275. H-Index II  🔗  📝
275. H-Index II  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Binary Search  🔗	274. H-Index  🔗  📝
276. Paint Fence  🔗  📝	💰		⭐️⭐️	Dynamic Programming  🔗	198. House Robber  🔗  📝 213. House Robber II  🔗  📝 256. Paint House  🔗  📝 265. Paint House II  🔗  📝
277. Find the Celebrity  🔗  📝	💰		⭐️⭐️	Two Pointers  🔗 Greedy  🔗 Graph  🔗 Interactive  🔗	997. Find the Town Judge  🔗  📝
278. First Bad Version  🔗  📝	🆓	✅	⭐️	Binary Search  🔗 Interactive  🔗	34. Find First and Last Position of Element in Sorted Array  🔗  📝 35. Search Insert Position  🔗  📝 374. Guess Number Higher or Lower  🔗  📝
279. Perfect Squares  🔗  📝	🆓	👀	⭐️⭐️	Math  🔗 Dynamic Programming  🔗 Breadth-First Search  🔗	204. Count Primes  🔗  📝 264. Ugly Number II  🔗  📝
280. Wiggle Sort  🔗  📝	💰		⭐️⭐️	Array  🔗 Greedy  🔗 Sorting  🔗	75. Sort Colors  🔗  📝 324. Wiggle Sort II  🔗  📝 1968. Array With Elements Not Equal to Average of Neighbors  🔗  📝
281. Zigzag Iterator  🔗  📝	💰		⭐️⭐️	Array  🔗 Design  🔗 Queue  🔗 Iterator  🔗	173. Binary Search Tree Iterator  🔗  📝 251. Flatten 2D Vector  🔗  📝 284. Peeking Iterator  🔗  📝 341. Flatten Nested List Iterator  🔗  📝 1768. Merge Strings Alternately  🔗  📝
282. Expression Add Operators  🔗  📝	🆓		⭐️⭐️⭐️	Math  🔗 String  🔗 Backtracking  🔗	150. Evaluate Reverse Polish Notation  🔗  📝 224. Basic Calculator  🔗  📝 227. Basic Calculator II  🔗  📝 241. Different Ways to Add Parentheses  🔗  📝 494. Target Sum  🔗  📝
283. Move Zeroes  🔗  📝	🆓	✅	⭐️	Array  🔗 Two Pointers  🔗	27. Remove Element  🔗  📝
284. Peeking Iterator  🔗  📝	🆓	👀	⭐️⭐️	Array  🔗 Design  🔗 Iterator  🔗	173. Binary Search Tree Iterator  🔗  📝 251. Flatten 2D Vector  🔗  📝 281. Zigzag Iterator  🔗  📝
285. Inorder Successor in BST  🔗  📝	💰		⭐️⭐️	Tree  🔗 Depth-First Search  🔗 Binary Search Tree  🔗 Binary Tree  🔗	94. Binary Tree Inorder Traversal  🔗  📝 173. Binary Search Tree Iterator  🔗  📝 510. Inorder Successor in BST II  🔗  📝
286. Walls and Gates  🔗  📝	💰		⭐️⭐️	Array  🔗 Breadth-First Search  🔗 Matrix  🔗	130. Surrounded Regions  🔗  📝 200. Number of Islands  🔗  📝 317. Shortest Distance from All Buildings  🔗  📝 489. Robot Room Cleaner  🔗  📝 994. Rotting Oranges  🔗  📝
287. Find the Duplicate Number  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Two Pointers  🔗 Binary Search  🔗 Bit Manipulation  🔗	41. First Missing Positive  🔗  📝 136. Single Number  🔗  📝 142. Linked List Cycle II  🔗  📝 268. Missing Number  🔗  📝 645. Set Mismatch  🔗  📝
288. Unique Word Abbreviation  🔗  📝	💰		⭐️⭐️	Array  🔗 Hash Table  🔗 String  🔗 Design  🔗	170. Two Sum III - Data structure design  🔗  📝 320. Generalized Abbreviation  🔗  📝
289. Game of Life  🔗  📝	🆓		⭐️⭐️	Array  🔗 Matrix  🔗 Simulation  🔗	73. Set Matrix Zeroes  🔗  📝
290. Word Pattern  🔗  📝	🆓	✅	⭐️	Hash Table  🔗 String  🔗	205. Isomorphic Strings  🔗  📝 291. Word Pattern II  🔗  📝
291. Word Pattern II  🔗  📝	💰		⭐️⭐️	Hash Table  🔗 String  🔗 Backtracking  🔗	290. Word Pattern  🔗  📝
292. Nim Game  🔗  📝	🆓		⭐️	Math  🔗 Brainteaser  🔗 Game Theory  🔗	294. Flip Game II  🔗  📝
293. Flip Game  🔗  📝	💰		⭐️	String  🔗	294. Flip Game II  🔗  📝
294. Flip Game II  🔗  📝	💰		⭐️⭐️	Math  🔗 Dynamic Programming  🔗 Backtracking  🔗 Memoization  🔗 Game Theory  🔗	292. Nim Game  🔗  📝 293. Flip Game  🔗  📝 375. Guess Number Higher or Lower II  🔗  📝 464. Can I Win  🔗  📝
295. Find Median from Data Stream  🔗  📝	🆓		⭐️⭐️⭐️	Two Pointers  🔗 Design  🔗 Sorting  🔗 Heap (Priority Queue)  🔗 Data Stream  🔗	480. Sliding Window Median  🔗  📝 1825. Finding MK Average  🔗  📝 2102. Sequentially Ordinal Rank Tracker  🔗  📝
296. Best Meeting Point  🔗  📝	💰		⭐️⭐️⭐️	Array  🔗 Math  🔗 Sorting  🔗 Matrix  🔗	317. Shortest Distance from All Buildings  🔗  📝 462. Minimum Moves to Equal Array Elements II  🔗  📝
297. Serialize and Deserialize Binary Tree  🔗  📝	🆓		⭐️⭐️⭐️	String  🔗 Tree  🔗 Depth-First Search  🔗 Breadth-First Search  🔗 Design  🔗 Binary Tree  🔗	271. Encode and Decode Strings  🔗  📝 428. Serialize and Deserialize N-ary Tree  🔗  📝 449. Serialize and Deserialize BST  🔗  📝 652. Find Duplicate Subtrees  🔗  📝
298. Binary Tree Longest Consecutive Sequence  🔗  📝	💰		⭐️⭐️	Tree  🔗 Depth-First Search  🔗 Binary Tree  🔗	128. Longest Consecutive Sequence  🔗  📝 549. Binary Tree Longest Consecutive Sequence II  🔗  📝 2229. Check if an Array Is Consecutive  🔗  📝
299. Bulls and Cows  🔗  📝	🆓		⭐️⭐️	Hash Table  🔗 String  🔗 Counting  🔗
300. Longest Increasing Subsequence  🔗  📝	🆓		⭐️⭐️	Array  🔗 Binary Search  🔗 Dynamic Programming  🔗	334. Increasing Triplet Subsequence  🔗  📝 354. Russian Doll Envelopes  🔗  📝 646. Maximum Length of Pair Chain  🔗  📝 673. Number of Longest Increasing Subsequence  🔗  📝 712. Minimum ASCII Delete Sum for Two Strings  🔗  📝 1671. Minimum Number of Removals to Make Mountain Array  🔗  📝 1964. Find the Longest Valid Obstacle Course at Each Position  🔗  📝 2111. Minimum Operations to Make the Array K-Increasing  🔗  📝 2355. Maximum Number of Books You Can Take  🔗  📝 2370. Longest Ideal Subsequence  🔗  📝