Problems

3,947+ problems · 946 Easy · 2062 Medium · 939 Hard

Active:Easy· 946 results

Title	Solution	Practice	Difficulty	Companies	Topics
202. Happy Number	Solution	Solve	Easy	Accenture+30	Hash Table Math+1
203. Remove Linked List Elements	Solution	Solve	Easy	Amazon+8	Linked List Recursion
205. Isomorphic Strings	Solution	Solve	Easy	Accenture+20	Hash Table String
206. Reverse Linked List	Solution	Solve	Easy	Accenture+35	Linked List Recursion
217. Contains Duplicate	Solution	Solve	Easy	Accenture+22	Array Hash Table+1
219. Contains Duplicate II	Solution	Solve	Easy	Accenture+13	Array Hash Table+1
222. Count Complete Tree Nodes	Solution	Solve	Easy	Adobe+6	Binary Search Binary Tree+2
225. Implement Stack using Queues	Solution	Solve	Easy	Amazon+8	Design Queue+1
226. Invert Binary Tree	Solution	Solve	Easy	Amazon+10	Binary Tree Breadth-First Search+2
228. Summary Ranges	Solution	Solve	Easy	Amazon+9	Array
231. Power of Two	Solution	Solve	Easy	Amazon+11	Bit Manipulation Math+1
232. Implement Queue using Stacks	Solution	Solve	Easy	Amazon+10	Design Queue+1
234. Palindrome Linked List	Solution	Solve	Easy	Adobe+17	Linked List Recursion+2
242. Valid Anagram	Solution	Solve	Easy	Accenture+40	Hash Table Sorting+1
243. Shortest Word Distance	Solution	Solve	Easy	Amazon+7	Array String
246. Strobogrammatic Number	Solution	Solve	Easy	Google+2	Hash Table String+1
252. Meeting Rooms	Solution	Solve	Easy	Amazon+9	Array Sorting
257. Binary Tree Paths	Solution	Solve	Easy	Amazon+7	Backtracking Binary Tree+3
258. Add Digits	Solution	Solve	Easy	Adobe+10	Math Number Theory+1
263. Ugly Number	Solution	Solve	Easy	Amazon+6	Math
266. Palindrome Permutation	Solution	Solve	Easy	Apple+7	Bit Manipulation Hash Table+1
268. Missing Number	Solution	Solve	Easy	Adobe+20	Array Binary Search+4
270. Closest Binary Search Tree Value	Solution	Solve	Easy	Amazon+8	Binary Search Binary Search Tree+3
278. First Bad Version	Solution	Solve	Easy	Adobe+6	Binary Search Interactive
283. Move Zeroes	Solution	Solve	Easy	Accenture+48	Array Two Pointers
290. Word Pattern	Solution	Solve	Easy	Amazon+9	Hash Table String
292. Nim Game	Solution	Solve	Easy	Adobe+5	Brainteaser Game Theory+1
293. Flip Game	Solution	Solve	Easy	Google	String
303. Range Sum Query - Immutable	Solution	Solve	Easy	Amazon+7	Array Design+1
326. Power of Three	Solution	Solve	Easy	Amazon+5	Math Recursion
338. Counting Bits	Solution	Solve	Easy	Adobe+8	Bit Manipulation Dynamic Programming
342. Power of Four	Solution	Solve	Easy	Amazon+7	Bit Manipulation Math+1
344. Reverse String	Solution	Solve	Easy	Accenture+15	String Two Pointers
345. Reverse Vowels of a String	Solution	Solve	Easy	Accenture+11	String Two Pointers
346. Moving Average from Data Stream	Solution	Solve	Easy	Amazon+8	Array Data Stream+2
349. Intersection of Two Arrays	Solution	Solve	Easy	Accenture+19	Array Binary Search+3
350. Intersection of Two Arrays II	Solution	Solve	Easy	Amazon+8	Array Binary Search+3
359. Logger Rate Limiter	Solution	Solve	Easy	Amazon+18	Data Stream Design+1
367. Valid Perfect Square	Solution	Solve	Easy	Amazon+6	Binary Search Math
374. Guess Number Higher or Lower	Solution	Solve	Easy	Amazon+6	Binary Search Interactive
383. Ransom Note	Solution	Solve	Easy	Amazon+11	Counting Hash Table+1
387. First Unique Character in a String	Solution	Solve	Easy	Accenture+24	Counting Hash Table+2
389. Find the Difference	Solution	Solve	Easy	Accenture+5	Bit Manipulation Hash Table+2
392. Is Subsequence	Solution	Solve	Easy	Adobe+18	Dynamic Programming String+1
401. Binary Watch	Solution	Solve	Easy	Amazon+4	Backtracking Bit Manipulation
404. Sum of Left Leaves	Solution	Solve	Easy	Amazon+6	Binary Tree Breadth-First Search+2
405. Convert a Number to Hexadecimal	Solution	Solve	Easy	Amazon+4	Bit Manipulation Math
408. Valid Word Abbreviation	Solution	Solve	Easy	Amazon+7	String Two Pointers
409. Longest Palindrome	Solution	Solve	Easy	Accenture+7	Greedy Hash Table+1
412. Fizz Buzz	Solution	Solve	Easy	Agoda+18	Math Simulation+1