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Leetcode (587/2561)

1. • 1. Two Sum ** Java✅ JavaScript✅
2. • 1281. Subtract the Product and Sum of Digits of an Integer
3. • 9. Palindrome Number
4. • 704. Binary Search
5. • 744. Find Smallest Letter Greater Than Target
6. • 34. Find First and Last Position of Element in Sorted Array *** Practise sometime later Java✅ JavaScript✅
7. • 852. Peak Index in a Mountain Array
8. • 162. Find Peak Element
9. • 268. Missing Number
10. • 448. Find All Numbers Disappeared in an Array **
11. • 2185. Counting Words With a Given Prefix Contest
12. • 287. Find the Duplicate Number *** Floyd's Cycle Detection (Tortoise & Hare) algo Practise sometime later
13. • 442. Find All Duplicates in an Array
14. • 2186. Minimum Number of Steps to Make Two Strings Anagram II *** Practise sometime later
15. • 645. Set Mismatch ***
16. • 41. First Missing Positive ***
17. • 278. First Bad Version **
18. • 35. Search Insert Position
19. • 1295. Find Numbers with Even Number of Digits
20. • 1672. Richest Customer Wealth
21. • 977. Squares of a Sorted Array **
22. • 189. Rotate Array ***
23. • 167. Two Sum II - Input Array Is Sorted **
24. • 283. Move Zeroes
25. • 344. Reverse String
26. • 557. Reverse Words in a String III ***
27. • 876. Middle of the Linked List Java✅ JavaScript✅
28. • 19. Remove Nth Node From End of List ***
29. • 1523. Count Odd Numbers in an Interval Range Tricky!
30. • 1491. Average Salary Excluding the Minimum and Maximum Salary
31. • 191. Number of 1 Bits
32. • 2194. Cells in a Range on an Excel Sheet **
33. • 2197. Replace Non-Coprime Numbers in Array ****
34. • 1779. Find Nearest Point That Has the Same X or Y Coordinate
35. • 1822. Sign of the Product of an Array
36. • 1502. Can Make Arithmetic Progression From Sequence
37. • 1920. Build Array from Permutation
38. • 1929. Concatenation of Array
39. • 69. Square Root **
40. • 1480. Running Sum of 1d Array
41. • 1431. Kids With the Greatest Number of Candies
42. • 2200. Find All K-Distant Indices in an Array
43. • 1512. Number of Good Pairs
44. • 1365. How Many Numbers Are Smaller Than the Current Number
45. • 374. Guess Number Higher or Lower ** Java✅ JavaScript✅
46. • 367. Valid Perfect Square **
47. • 66. Plus One
48. • 1572. Matrix Diagonal Sum **
49. • 1470. Shuffle the Array
50. • 1389. Create Target Array in the Given Order
51. • 1832. Check if the Sentence Is Pangram Java✅ JavaScript✅
52. • 2206. Divide Array Into Equal Pairs
53. • 2210. Count Hills and Valleys in an Array **
54. • 832. Flipping an Image
55. • 1773. Count Items Matching a Rule
56. • 1732. Find the Highest Altitude
57. • 1252. Cells with Odd Values in a Matrix ****
58. • 867. Transpose Matrix
59. • 989. Add to Array-Form of Integer **
60. • 1854. Maximum Population Year *** Practise sometime later
61. • 1342. Number of Steps to Reduce a Number to Zero
62. • 1304. Find N Unique Integers Sum up to Zero
63. • 1380. Lucky Numbers in a Matrix
64. • 26. Remove Duplicates from Sorted Array * Java✅ JavaScript✅
65. • 1217. Minimum Cost to Move Chips to The Same Position Tricky!
66. • 441. Arranging Coins(Easy) *
67. • 1539. Kth Missing Positive Number ***
68. • 1351. Count Negative Numbers in a Sorted Matrix Practise sometime later
69. • 349. Intersection of Two Arrays
70. • 350. Intersection of Two Arrays II
71. • 888. Fair Candy Swap ** Math Practise sometime later
72. • 1346. Check If N and Its Double Exist ** Tricky! Practise sometime later
73. • 1608. Special Array With X Elements Greater Than or Equal X **
74. • 53. Maximum Subarray *** Practise sometime later
75. • 2215. Find the Difference of Two Arrays
76. • 2216. Minimum Deletions to Make Array Beautiful *** Practise sometime later
77. • 33. Search in Rotated Sorted Array **
78. • 81. Search in Rotated Sorted Array II **
79. • 1108. Defanging an IP Address
80. • 74. Search a 2D Matrix *** Practise sometime later
81. • 1528. Shuffle String
82. • 410. Split Array Largest Sum **** Important Practise sometime later
83. • 1678. Goal Parser Interpretation
84. • 1859. Sorting the Sentence **
85. • 1662. Check If Two String Arrays are Equivalent
86. • 709. To Lower Case
87. • 88. Merge Sorted Array ***
88. • 169. Majority Element ** Boyer-Moore Voting algo Practise sometime later
89. • 217. Contains Duplicate
90. • 680. Valid Palindrome II **
91. • 2220. Minimum Bit Flips to Convert Number **
92. • 2221. Find Triangular Sum of an Array ** Practise sometime later
93. • 2222. Number of Ways to Select Buildings *** Practise sometime later
94. • 2224. Minimum Number of Operations to Convert Time **
95. • 67. Add Binary
96. • 136. Single Number
97. • 215. Kth Largest Element in an Array **
98. • 1704. Determine if String Halves Are Alike **
99. • 11. Container With Most Water ** Practise sometime later
100. • 238. Product of Array Except Self *** Practise sometime later
101. • 509. Fibonacci Number
102. • 231. Power of Two
103. • 326. Power of Three
104. • 342. Power of Four
105. • 1886. Determine Whether Matrix Can Be Obtained By Rotation *** Practise sometime later
106. • 566. Reshape the Matrix **
107. • 1046. Last Stone Weight **
108. • 12. Integer to Roman **
109. • 168. Excel Sheet Column Title **
110. • 628. Maximum Product of Three Numbers **
111. • 2231. Largest Number After Digit Swaps by Parity ***
112. • 1260. Shift 2D Grid **
113. • 2235. Add Two Integers Never solve again
114. • 2236. Root Equals Sum of Children
115. • 2239. Find Closest Number to Zero **
116. • 2240. Number of Ways to Buy Pens and Pencils ***
117. • 2243. Calculate Digit Sum of a String **
118. • 2244. Minimum Rounds to Complete All Tasks *** Practise sometime later
119. • 412. Fizz Buzz *
120. • 28. Implement strStr() *** KMP Practise sometime later
121. • 70. Climbing Stairs ** DP Practise sometime later
122. • 125. Valid Palindrome **
123. • 58. Length of Last Word
124. • 7. Reverse Integer *
125. • 540. Single Element in a Sorted Array **
126. • 54. Spiral Matrix ***
127. • 153. Find Minimum in Rotated Sorted Array ***
128. • 59. Spiral Matrix II
129. • 2248. Intersection of Multiple Arrays
130. • 1396. Design Underground System ** Practise sometime later
131. • 2249. Count Lattice Points Inside a Circle **
132. • 2251. Number of Flowers in Full Bloom **** Practise sometime later
133. • 2250. Count Number of Rectangles Containing Each Point **** Practise Tricky!
134. • 73. Set Matrix Zeroes **
135. • 885. Spiral Matrix III *** Practise sometime later
136. • 75. Sort Colors *
137. • 198. House Robber ** DP Practise sometime later Tricky!
138. • 55. Jump Game *** Practise sometime later DP Greedy Java✅ JavaScript✅
139. • 600. Non-negative Integers without Consecutive Ones **** Practise sometime later DP
140. • 1250. Check If It Is a Good Array *** Mathematical
141. • 436. Find Right Interval ***
142. • 179. Largest Number ***
143. • 2. Add Two Numbers *** Practise sometime later
144. • 83. Remove Duplicates from Sorted List **
145. • 21. Merge Two Sorted Lists **
146. • 141. Linked List Cycle *
147. • 142. Linked List Cycle II ** Practise sometime later
148. • 202. Happy Number ** LL slow-fast approach used Tricky!
149. • 2095. Delete the Middle Node of a Linked List ** Java✅ JavaScript✅
150. • 876. Middle of the Linked List *
151. • 148. Sort List *** Practise sometime later
152. • 147. Insertion Sort List **
153. • 206. Reverse Linked List * Practise sometime later
154. • 905. Sort Array By Parity ** Take a look later
155. • 2255. Count Prefixes of a Given String * nice use String.prototype.indexOf()
156. • 2256. Minimum Average Difference ** Java✅ JavaScript✅
157. • 2257. Count Unguarded Cells in the Grid *** Practise sometime later
158. • 2211. Count Collisions on a Road *** Tricky!
159. • 92. Reverse Linked List II *** Practise sometime later
160. • 234. Palindrome Linked List *** Practise sometime later
161. • 143. Reorder List *** Practise sometime later
162. • 25. Reverse Nodes in k-Group **** Practise sometime later
163. • 61. Rotate List *** Practise sometime later
164. • 48. Rotate Image ***
165. • 2259. Remove Digit From Number to Maximize Result ** Use substring
166. • 2260. Minimum Consecutive Cards to Pick Up *** Practise sometime later
167. • 2261. K Divisible Elements Subarrays ***
168. • 2262. Total Appeal of A String ***
169. • 242. Valid Anagram
170. • 27. Remove Element *
171. • 414. Third Maximum Number *
172. • 2264. Largest 3-Same-Digit Number in String *
173. • 2266. Count Number of Texts *** Practise sometime later
174. • 2265. Count Nodes Equal to Average of Subtree **
175. • 1499. Max Value of Equation ****
176. • 754. Reach a Number ***
177. • 1802. Maximum Value at a Given Index in a Bounded Array *** Practise sometime later
178. • 875. Koko Eating Bananas ***
179. • 233. Number of Digit One ***
180. • 1818. Minimum Absolute Sum Difference *** Practise sometime later
181. • 1901. Find a Peak Element II ***
182. • 1838. Frequency of the Most Frequent Element **
183. • 154. Find Minimum in Rotated Sorted Array II ***
184. • 4. Median of Two Sorted Arrays ***
185. • 1011. Capacity To Ship Packages Within D Days **
186. • 1095. Find in Mountain Array *** Take a look again sometime later
187. • 315. Count of Smaller Numbers After Self **** Practise again
188. • 976. Largest Perimeter Triangle *
189. • 1309. Decrypt String from Alphabet to Integer Mapping
190. • 1967. Number of Strings That Appear as Substrings in Word
191. • 657. Robot Return to Origin
192. • 2269. Find the K-Beauty of a Number
193. • 2270. Number of Ways to Split Array **
194. • 2273. Find Resultant Array After Removing Anagrams *
195. • 2274. Maximum Consecutive Floors Without Special Floors **
196. • 2275. Largest Combination With Bitwise AND Greater Than Zero **
197. • 455. Assign Cookies Greedy
198. • 561. Array Partition I Pattern after sorting
199. • 922. Sort Array By Parity II
200. • 1030. Matrix Cells in Distance Order **
201. • 1051. Height Checker
202. • 1122. Relative Sort Array *
203. • 1200. Minimum Absolute Difference *
204. • 1331. Rank Transform of an Array *
205. • 1356. Sort Integers by The Number of 1 Bits **
206. • 1464. Maximum Product of Two Elements in an Array
207. • 1460. Make Two Arrays Equal by Reversing Sub-arrays
208. • 1636. Sort Array by Increasing Frequency *
209. • 15. 3 Sum *** Practise sometime later
210. • 16. 3 Sum Closest ***
211. • 13. Roman to Integer.
212. • 925. Long Pressed Name *
213. • 18. 4 Sum *** Practise sometime later
214. • 49. Group Anagrams *** Java✅ JavaScript✅
215. • 56. Merge Intervals *** Meeting Room I & II Similar Practise again
216. • 435. Non-overlapping Intervals **
217. • 1784. Check if Binary String Has at Most One Segment of Ones
218. • 1768. Merge Strings Alternately
219. • 2278. Percentage of Letter in String
220. • 2279. Maximum Bags With Full Capacity of Rocks ** Java✅ JavaScript✅
221. • 2280. Minimum Lines to Represent a Line Chart ***
222. • 647. Palindromic Substrings ***
223. • 1871. Jump Game VII **
224. • 14. Longest Common Prefix **
225. • 1668. Maximum Repeating Substring **
226. • 2000. Reverse Prefix of Word
227. • 20. Valid Parentheses
228. • 190. Reverse Bits **
229. • 401. Binary Watch **
230. • 50. Pow(x, n) **
231. • 1486. XOR Operation in an Array
232. • 728. Self Dividing Numbers
233. • 1720. Decode XORed Array
234. • 1863. Sum of All Subset XOR Totals **
235. • 78. Subsets **
236. • 2283. Check if Number Has Equal Digit Count and Digit Value
237. • 2284. Sender With Largest Word Count **
238. • 2287. Rearrange Characters to Make Target String
239. • 2285. Maximum Total Importance of Roads ***
240. • 2288. Apply Discount to Prices ***
241. • 29. Divide Two Integers **
242. • 1616. Split Two Strings to Make Palindrome ***
243. • 1573. Number of Ways to Split a String **
244. • 1813. Sentence Similarity III **
245. • 23. Merge k Sorted Lists ****
246. • 312. Burst Balloons **** DP Practise sometime later
247. • 304. Range Sum Query 2D - Immutable *** Practise sometime later
248. • 38. Count and Say ***
249. • 51. N Queens *** Practise sometime later
250. • 65. Valid Number ***
251. • 2293. Min Max Game
252. • 2294. Partition Array Such That Maximum Difference Is K ***
253. • 2295. Replace Elements in an Array **
254. • 52. N Queens II ***
255. • 160. Intersection of Two Linked Lists *
256. • 461. Hamming Distance
257. • 477. Total Hamming Distance **
258. • 1332. Remove Palindromic Subsequences
259. • 693. Binary Number with Alternating Bits
260. • 476. Number Complement *
261. • 1009. Complement of Base 10 Integer
262. • 90. Subsets II ***
263. • 3. Longest Substring Without Repeating Characters ***
264. • 762. Prime Number of Set Bits in Binary Representation *
265. • 2299. Strong Password Checker II *
266. • 2300. Successful Pairs of Spells and Potions ***
267. • 2302. Count Subarrays With Score Less Than K *** Practise sometime later
268. • 2303. Calculate Amount Paid in Taxes *
269. • 2304. Minimum Path Cost in a Grid *** Solve again later
270. • 868. Binary Gap
271. • 1684. Count the Number of Consistent Strings
272. • 686. Repeated String Match **
273. • 120. Triangle **
274. • 583. Delete Operation for Two Strings *** DP Solve again later
275. • 137. Single Number II **
276. • 1763. Longest Nice Substring *** DP Solve again later Recursion
277. • 89. Gray Code ***
278. • 187. Repeated DNA Sequences **
279. • 968. Binary Tree Cameras **** Solve again later
280. • 121. Best Time to Buy and Sell Stock ** Not so easy
281. • 240. Search a 2D Matrix II ***
282. • 2309. Greatest English Letter in Upper and Lower Case
283. • 2310. Sum of Numbers With Units Digit K *** Tricky! Practise sometime later
284. • 2311. Longest Binary Subsequence Less Than or Equal to K **
285. • 89. Gray Code ** Not so easy
286. • 1268. Search Suggestions System ***
287. • 820. Short Encoding of Words *** set substring
288. • 703. Kth Largest Element in a Stream *** Solve again later
289. • 1985. Find the Kth Largest Integer in the Array *** Tricky!
290. • 1835. Find XOR Sum of All Pairs Bitwise AND Tricky!
291. • 2226. Maximum Candies Allocated to K Children *** Nice Binary Search Q
292. • 1757. Recyclable and Low Fat Products
293. • 2011. Final Value of Variable After Performing Operations
294. • 2114. Maximum Number of Words Found in Sentences
295. • 1313. Decompress Run-Length Encoded List
296. • 2315. Count Asterisks
297. • 1689. Partitioning Into Minimum Number Of Deci-Binary Numbers Tricky! Easy
298. • 2319. Check if Matrix Is X-Matrix
299. • 2317. Maximum XOR After Operations *** Tricky!
300. • 237. Delete Node in a Linked List Tricky! Easy
301. • 1290. Convert Binary Number in a Linked List to Integer
302. • 203. Remove Linked List Elements
303. • 82. Remove Duplicates from Sorted List II ***
304. • 1710. Maximum Units on a Truck **
305. • 445. Add Two Numbers II *** Solve again later Imp
306. • 1721. Swapping Nodes in a Linked List ***
307. • 496. Next Greater Element I ** Make it more optimised
308. • 503. Next Greater Element II *** Stack
309. • 146. LRU Cache **** Solve again later
310. • 225. Implement Stack using Queues **
311. • 232. Implement Queue using Stacks **
312. • 1974. Minimum Time to Type Word Using Special Typewriter *
313. • 2331. Evaluate Boolean Binary Tree
314. • 2333. Minimum Sum of Squared Difference ***
315. • 2335. Minimum Amount of Time to Fill Cups *** Tricky!
316. • 2336. Smallest Number in Infinite Set **
317. • 2337. Move Pieces to Obtain a String *** Practise sometime later
318. • 39. Combination Sum *** Recursion Solve again using dfs
319. • 40. Combination Sum II *** Recursion
320. • 46. Permutations ** Recursion
321. • 47. Permutations II ** Recursion
322. • 37. Sudoku Solver **** Backtracking Practise sometime later
323. • 171. Excel Sheet Column Number *
324. • 36. Valid Sudoku*** Practise sometime later
325. • 239. Sliding Window Maximum *** Important!! Dequeue Solve again later
326. • 2119. A Number After a Double Reversal
327. • 917. Reverse Only Letters *
328. • 994. Rotting Oranges *** BFS
329. • 493. Reverse Pairs **** Solve again later
330. • 84. Largest Rectangle in Histogram **** Stack Practise sometime later
331. • 131. Palindrome Partitioning *** Backtracking
332. • 118. Pascal's Triangle *
333. • 2341. Maximum Number of Pairs in Array
334. • 2325. Decode the Message
335. • 2326. Spiral Matrix IV **
336. • 60. Permutation Sequence **** Tricky!
337. • 86. Partition List **
338. • 2161. Partition Array According to Given Pivot *
339. • 2149. Rearrange Array Elements by Sign **
340. • 2347. Best Poker Hand
341. • 2348. Number of Zero-Filled Subarrays **
342. • 2351. First Letter to Appear Twice
343. • 2352. Equal Row and Column Pairs **
344. • 2350. Shortest Impossible Sequence of Rolls **** Tricky! Solve again later
345. • 236. Lowest Common Ancestor of a Binary Tree *** DFS
346. • 213. House Robber II ** DP
347. • 119. Pascal's Triangle II
348. • 890. Find and Replace Pattern **
349. • 62. Unique Paths *** DP
350. • 416. Partition Equal Subset Sum *** DP Practise sometime later
351. • 63. Unique Paths II *** DP
352. • 371. Sum of Two Integers Tricky!
353. • 64. Minimum Path Sum *** DP
354. • 252. Meeting Rooms 🔒 *
355. • 2357. Make Array Zero by Subtracting Equal Amounts
356. • 2358. Maximum Number of Groups Entering a Competition ** Tricky!
357. • 409. Longest Palindrome ** Greedy
358. • 378. Kth Smallest Element in a Sorted Matrix *** BS
359. • 746. Min Cost Climbing Stairs *
360. • 2320. Count Number of Ways to Place Houses ** DP
361. • 858. Mirror Reflection ** Geometry Practise sometime later
362. • 1302. Deepest Leaves Sum ** BinaryTree
363. • 377. Combination Sum IV *** DP
364. • 2181. Merge Nodes in Between Zeros *
365. • 100. Same Tree
366. • 1379. Find a Corresponding Node of a Binary Tree in a Clone of That Tree
367. • 1038. Binary Search Tree to Greater Sum Tree *** Practise sometime later
368. • 538. Convert BST to Greater Tree Same as above
369. • 2367. Number of Arithmetic Triplets *
370. • 2368. Reachable Nodes With Restrictions *** DFS BFS Practise sometime later
371. • 2369. Check if There is a Valid Partition For The Array *** DP
372. • 144. Binary Tree Preorder Traversal
373. • 94. Binary Tree Inorder Traversal Morris Traversal ✅
374. • 145. Binary Tree Postorder Traversal
375. • 102. Binary Tree Level Order Traversal *** BFS
376. • 823. Binary Trees With Factors **** DP Hashmap
377. • 300. Longest Increasing Subsequence ** Dp Greedy BS
378. • 1828. Queries on Number of Points Inside a Circle *
379. • 108. Convert Sorted Array to Binary Search Tree **
380. • 105. Construct Binary Tree from Preorder and Inorder Traversal ***
381. • 106. Construct Binary Tree from Inorder and Postorder Traversal ***
382. • 104. Maximum Depth of Binary Tree ** DFS BFS
383. • 111. Minimum Depth of Binary Tree * DFS BFS
384. • 124. Binary Tree Maximum Path Sum ****
385. • 543. Diameter of Binary Tree ** Imp Concept
386. • 110. Balanced Binary Tree **
387. • 103. Binary Tree Zigzag Level Order Traversal ***
388. • 2363. Merge Similar Items
389. • 2305. Fair Distribution of Cookies ***
390. • 2373. Largest Local Values in a Matrix
391. • 2374. Node With Highest Edge Score ***
392. • 545. Boundary of Binary Tree 🔒 ***
393. • 987. Vertical Order Traversal of a Binary Tree ****
394. • 387. First Unique Character in a String **
395. • 199. Binary Tree Right Side View **
396. • 101. Symmetric Tree *
397. • 637. Average of Levels in Binary Tree *
398. • 1338. Reduce Array Size to The Half **
399. • 107. Binary Tree Level Order Traversal II **
400. • 2379. Minimum Recolors to Get K Consecutive Black Blocks **
401. • 2380. Time Needed to Rearrange a Binary String **
402. • 2381. Shifting Letters II *** Optimization is important
403. • 2383. Minimum Hours of Training to Win a Competition
404. • 134. Gas Station *** Greedy Java✅ JavaScript✅
405. • 931. Minimum Falling Path Sum *** DP
406. • 116. Populating Next Right Pointers in Each Node ***
407. • 1289. Minimum Falling Path Sum II **** DP
408. • 1463. Cherry Pickup II **** DP Solve again later
409. • 662. Maximum Width of Binary Tree *** Practise sometime later
410. • 2385. Amount of Time for Binary Tree to Be Infected *** Practise sometime later
411. • 863. All Nodes Distance K in Binary Tree *** Practise sometime later
412. • 383. Ransom Note
413. • 2202. Maximize the Topmost Element After K Moves ***
414. • 2217. Find Palindrome With Fixed Length *** Practise sometime later
415. • 1329. Sort the Matrix Diagonally ***
416. • 871. Minimum Number of Refueling Stops **** Practise sometime later
417. • 2218. Maximum Value of K Coins From Piles **** DP
418. • 1448. Count Good Nodes in Binary Tree ** DFS
419. • 2201. Count Artifacts That Can Be Extracted ***
420. • 2169. Count Operations to Obtain Zero
421. • 2170. Minimum Operations to Make the Array Alternating *** Greedy Practise sometime later
422. • 2171. Removing Minimum Number of Magic Beans *** Tricky!
423. • 222. Count Complete Tree Nodes **
424. • 2400. Number of Ways to Reach a Position After Exactly k Steps *** Combinatorics - Math
425. • 2391. Minimum Amount of Time to Collect Garbage **
426. • 814. Binary Tree Pruning **
427. • 429. N-ary Tree Level Order Traversal ***
428. • 98. Validate Binary Search Tree *** Imp
429. • 297. Serialize and Deserialize Binary Tree *** Imp Nice Ques
430. • 2404. Most Frequent Even Element *
431. • 200. Number of Islands *** Graph Practise sometime later
432. • 2405. Optimal Partition of String **
433. • 733. Flood Fill
434. • 114. Flatten Binary Tree to Linked List **
435. • 2415. Reverse Odd Levels of Binary Tree **
436. • 260. Single Number III *** Bit Manipulation Practise sometime later
437. • 201. Bitwise AND of Numbers Range ** Tricky!
438. • 700. Search in a Binary Search Tree
439. • 701. Insert into a Binary Search Tree *
440. • 1344. Angle Between Hands of a Clock
441. • 450. Delete Node in a BST ***
442. • 230. Kth Smallest Element in a BST **
443. • 235. Lowest Common Ancestor of a Binary Search Tree ***
444. • 1008. Construct Binary Search Tree from Preorder Traversal ** Practise again - Optimized approach
445. • 285. Inorder Successor in BST 🔒 **
446. • 285. Inorder Predecessor in BST 🔒
447. • 173. Binary Search Tree Iterator **
448. • 653. Two Sum IV - Input is a BST *
449. • 99. Recover Binary Search Tree **
450. • 333. Largest BST Subtree 🔒 ***
451. • 109. Convert Sorted List to Binary Search Tree ***
452. • 2419. Longest Subarray With Maximum Bitwise AND
453. • 2410. Maximum Matching of Players With Trainers **
454. • 130. Surrounded Regions *** Nice Q
455. • 2413. Smallest Even Multiple
456. • 1020. Number of Enclaves **
457. • 547. Number of Provinces *
458. • 2418. Sort the People
459. • 2150. Find All Lonely Numbers in the Array ***
460. • 694. Number of Distinct Islands 🔒 ***
461. • 658. Find K Closest Elements *** Nice Q BS Java✅ JavaScript✅
462. • 802. Find Eventual Safe States *** Using DFS
463. • 207. Course Schedule *** Using topo sort
464. • 210. Course Schedule II ***
465. • 2433. Find The Original Array of Prefix Xor
466. • 328. Odd Even Linked List ***
467. • 707. Design Linked List ***
468. • 269. Alien Dictionary 🔒 ****
469. • 2428. Maximum Sum of an Hourglass * Java✅ JavaScript✅
470. • 560. Subarray Sum Equals K *** Practise sometime later Java✅ JavaScript✅
471. • 2442. Count Number of Distinct Integers After Reverse Operations ** Java✅ JavaScript✅
472. • 219. Contains Duplicate II * Java✅ JavaScript✅
473. • 1047. Remove All Adjacent Duplicates In String * Stack Java✅ JavaScript✅
474. • 1884. Egg Drop With 2 Eggs and N Floors *** Tricky! DP Practise sometime later Java✅ JavaScript✅
475. • 2414. Length of the Longest Alphabetical Continuous Substring *** Practise sometime later Java✅ JavaScript✅
476. • 2441. Largest Positive Integer That Exists With Its Negative Java✅ JavaScript✅
477. • 523. Continuous Subarray Sum *** Practise sometime later Java✅ JavaScript✅
478. • 1171. Remove Zero Sum Consecutive Nodes from Linked List *** Java✅ JavaScript✅
479. • 127. Word Ladder **** BFS Java✅ JavaScript✅
480. • 2455. Average Value of Even Numbers That Are Divisible by Three
481. • 2456. Most Popular Video Creator **
482. • 2457. Minimum Addition to Make Integer Beautiful ***
483. • 766. Toeplitz Matrix * Java✅ JavaScript✅
484. • 2452. Words Within Two Edits of Dictionary * Java✅ JavaScript✅
485. • 2079. Watering Plants * Java✅ JavaScript✅
486. • 1980. Find Unique Binary String ** Java✅ JavaScript✅
487. • 1860. Incremental Memory Leak ** Java✅ JavaScript✅
488. • 345. Reverse Vowels of a String *
489. • 1963. Minimum Number of Swaps to Make the String Balanced ** Java✅ JavaScript✅
490. • 2460. Apply Operations to an Array Java✅ JavaScript✅
491. • 1323. Maximum 69 Number Java✅ JavaScript✅
492. • 1910. Remove All Occurrences of a Substring *** Practise with KMP Java✅ JavaScript✅
493. • 901. Online Stock Span **
494. • 1877. Minimize Maximum Pair Sum in Array * Java✅ JavaScript✅
495. • 1861. Rotating the Box **
496. • 151. Reverse Words in a String *
497. • 2469. Convert the Temperature
498. • 2465. Number of Distinct Averages
499. • 2461. Maximum Sum of Distinct Subarrays With Length K **
500. • 2427. Number of Common Factors
501. • 1409. Queries on a Permutation With Key *** Practise optimized approach using Fenwick tree
502. • 223. Rectangle Area *
503. • 263. Ugly Number
504. • 2471. Minimum Number of Operations to Sort a Binary Tree by Level ** Java✅ JavaScript✅
505. • 2447. Number of Subarrays With GCD Equal to K ***
506. • 2401. Longest Nice Subarray *** Sliding Window Bit Manipulation Java✅ JavaScript✅
507. • 279. Perfect Squares *** DP Java✅ JavaScript✅
508. • 2476. Closest Nodes Queries in a Binary Search Tree *** Practise sometime later
509. • 2446. Determine if Two Events Have Conflict
510. • 541. Reverse String II
511. • 2177. Find Three Consecutive Integers That Sum to a Given Number
512. • 2481. Minimum Cuts to Divide a Circle
513. • 2482. Difference Between Ones and Zeros in Row and Column ** Java✅ JavaScript✅
514. • 2483. Minimum Penalty for a Shop *** Java✅ JavaScript✅
515. • 413. Arithmetic Slices ** Java✅ JavaScript✅
516. • 2225. Find Players With Zero or One Losses **
517. • 2485. Find the Pivot Integer
518. • 2487. Remove Nodes From Linked List ** Java✅ JavaScript✅
519. • 1207. Unique Number of Occurrences
520. • 1992. Find All Groups of Farmland ***
521. • 1657. Determine if Two Strings Are Close ** Java✅ little tricky!
522. • 446. Arithmetic Slices II - Subsequence **** Practise sometime later DP Java✅
523. • 451. Sort Characters By Frequency *** Practise sometime later JavaScript✅
524. • 2491. Divide Players Into Teams of Equal Skill ** Java✅ JavaScript✅
525. • 1780. Check if Number is a Sum of Powers of Three ** Math Java✅ JavaScript✅
526. • 2443. Sum of Number and Its Reverse * Math Java✅ JavaScript✅
527. • 938. Range Sum of BST Java✅ JavaScript✅
528. • 24. Swap Nodes in Pairs * Java✅ JavaScript✅
529. • 872. Leaf-Similar Trees
530. • 1026. Maximum Difference Between Node and Ancestor *** Practise sometime later
531. • 2496. Maximum Value of a String in an Array
532. • 2500. Delete Greatest Value in Each Row
533. • 2432. The Employee That Worked on the Longest Task
534. • 1991. Find the Middle Index in Array ** Nice Q
535. • 2490. Circular Sentence
536. • 739. Daily Temperatures **
537. • 2501. Longest Square Streak in an Array ***
538. • 841. Keys and Rooms **
539. • 2032. Two Out of Three * Practise BitMask method
540. • 2506. Count Pairs Of Similar Strings *
541. • 309. Best Time to Buy and Sell Stock with Cooldown *** Practise again
542. • 2037. Minimum Number of Moves to Seat Everyone
543. • 2389. Longest Subsequence With Limited Sum *
544. • 2507. Smallest Value After Replacing With Sum of Prime Factors **
545. • 2509. Cycle Length Queries in a Tree *** Practise again
546. • 150. Evaluate Reverse Polish Notation ** Java✅ JavaScript✅
547. • 2512. Reward Top K Students *** Practise sometime later
548. • 290. Word Pattern *
549. • 520. Detect Capital *
550. • 944. Delete Columns to Make Sorted Java✅ JavaScript✅
551. • 2520. Count the Digits That Divide a Number
552. • 452. Minimum Number of Arrows to Burst Balloons *** Greedy
553. • 1833. Maximum Ice Cream Bars ** Greedy
554. • 149. Max Points on a Line *** Math
555. • 2515. Shortest Distance to Target String in a Circular Array
556. • 30. Substring with Concatenation of All Words **** Sliding Window Practise sometime later
557. • 1443. Minimum Time to Collect All Apples in a Tree *** Practise again
558. • 1519. Number of Nodes in the Sub-Tree With the Same Label
559. • 2246. Longest Path With Different Adjacent Characters ****
560. • 1061. Lexicographically Smallest Equivalent String
561. • 57. Insert Interval ***
562. • 926. Flip String to Monotone Increasing *** Java✅
563. • 918. Maximum Sum Circular Subarray *** Java✅ JavaScript✅
564. • 974. Subarray Sums Divisible by K ***
565. • 491. Non-decreasing Subsequences *** Java✅
566. • 93. Restore IP Addresses *** JavaScript✅
567. • 2535. Difference Between Element Sum and Digit Sum of an Array
568. • 997. Find the Town Judge
569. • 909. Snakes and Ladders *** JavaScript✅
570. • 2359. Find Closest Node to Given Two Nodes *** Java✅
571. • 787. Cheapest Flights Within K Stops **** Java✅
572. • 472. Concatenated Words **** JavaScript✅
573. • 352. Data Stream as Disjoint Intervals **** BS Design JavaScript✅
574. • 460. LFU Cache **** Design Need much more Practise for implementation Java✅
575. • 1137. N-th Tribonacci Number
576. • 1626. Best Team With No Conflicts **** JavaScript✅
577. • 1071. Greatest Common Divisor of Strings
578. • 2545. Sort the Students by Their Kth Score *
579. • 2544. Alternating Digit Sum
580. • 2529. Maximum Count of Positive Integer and Negative Integer
581. • 2553. Separate the Digits in an Array
582. • 2527. Find Xor-Beauty of Array
583. • 2558. Take Gifts From the Richest Pile *
584. • 45. Jump Game II ***
585. • 2073. Time Needed to Buy Tickets
586. • 2549. Count Distinct Numbers on Board
587. • 2517. Maximum Tastiness of Candy Basket ** BS

Other Platforms

1. • HackerRank Problems - Solutions
2. • GeeksForGeeks Problems - Solutions
3. • Rat in a Maze Problem - I *** GFG
4. • Subset Sums ** GFG
5. • Frog Jump *
6. • Maximum sum of non-adjacent elements * Like House Robber
7. • Ninja’s Training *** DP
8. • Unique Paths
9. • Subset Sum Problem ** GFG
10. • N meetings in one room ** Greedy GFG
11. • Minimum Platforms *** Greedy GFG
12. • Boundary Traversal of binary tree *** GFG
13. • Top View of Binary Tree *** GFG
14. • Bottom View of Binary Tree ** GFG
15. • Path to Given Node **
16. • Mirror Tree * GFG
17. • Angle between hour and minute hand GFG
18. • Number of Provinces *** GFG
19. • Minimum cost of choosing 3 increasing elements in an array of size N *** GFG Practise sometime later
20. • Find the number of islands *** 8 directions Number of Islands - 4 directions
21. • Max Non Negative SubArray **
22. • Detect cycle in an undirected graph
23. • Largest BST *** GFG
24. • Replace O's with X's *** GFG
25. • Number Of Enclaves ** GFG
26. • Number of Distinct Islands *** GFG
27. • Bipartite Graph *** GFG
28. • Detect cycle in a directed graph *** GFG
29. • Topological sort Imp GFG
30. • Eventual Safe States **
31. • Prerequisite Tasks
32. • Course Schedule **
33. • Alien Dictionary ***
34. • Zero Sum Subarrays **
35. • Egg Dropping Puzzle *** GFG DP
36. • Shortest path in Directed Acyclic Graph
37. • Shortest path in Undirected Graph having unit distance
38. • Word Ladder I
39. • Amazing Subarrays