Dashboard Questions Topics Companies Sheets

Data Structures & Algorithms

Practice 3,374+ coding problems from top companies. Master DSA concepts and ace your interviews.

3,374

Problems

840

Easy

1762

Medium

772

Hard

Difficulty

All3374 Easy840 Medium1762 Hard772

Title	Solve	Difficulty	Companies	Topics
202. Happy Number	Solve	Easy	Adobe+5	Hash Table Math+1
203. Remove Linked List Elements	Solve	Easy	Adobe+3	Linked List Recursion
205. Isomorphic Strings	Solve	Easy	Amazon+2	Hash Table String
206. Reverse Linked List	Solve	Easy	Amazon+8	Linked List Recursion
217. Contains Duplicate	Solve	Easy	Adobe+8	Array Hash Table+1
219. Contains Duplicate II	Solve	Easy	Adobe+6	Array Hash Table+1
222. Count Complete Tree Nodes	Solve	Easy	Amazon+2	Binary Search Binary Tree+2
225. Implement Stack using Queues	Solve	Easy	Accenture+54	Design Queue+1
226. Invert Binary Tree	Solve	Easy	Amazon+5	Binary Tree Breadth-First Search+2
228. Summary Ranges	Solve	Easy	Adobe+7	Array
231. Power of Two	Solve	Easy	Amazon+3	Bit Manipulation Math+1
232. Implement Queue using Stacks	Solve	Easy	Amazon+4	Design Queue+1
234. Palindrome Linked List	Solve	Easy	Adobe+10	Linked List Recursion+2
242. Valid Anagram	Solve	Easy	Affirm+8	Hash Table Sorting+1
243. Shortest Word Distance	Solve	Easy	Amazon+4	Array String
246. Strobogrammatic Number	Solve	Easy	Facebook+1	Hash Table String+1
252. Meeting Rooms	Solve	Easy	Amazon+1	Array Sorting
257. Binary Tree Paths	Solve	Easy	Amazon+4	Backtracking Binary Tree+3
258. Add Digits	Solve	Easy	Bloomberg	Math Number Theory+1
263. Ugly Number	Solve	Easy	Adobe+4	Math
266. Palindrome Permutation	Solve	Easy	Facebook	Bit Manipulation Hash Table+1
268. Missing Number	Solve	Easy	Adobe+8	Array Binary Search+4
270. Closest Binary Search Tree Value	Solve	Easy	Facebook	Binary Search Binary Search Tree+3
278. First Bad Version	Solve	Easy	Adobe+6	Binary Search Interactive
283. Move Zeroes	Solve	Easy	Adobe+11	Array Two Pointers
290. Word Pattern	Solve	Easy	Adobe+3	Hash Table String
292. Nim Game	Solve	Easy	Adobe+1	Brainteaser Game Theory+1
293. Flip Game	Solve	Easy	Google	String
303. Range Sum Query - Immutable	Solve	Easy	Facebook	Array Design+1
326. Power of Three	Solve	Easy	Amazon	Math Recursion
338. Counting Bits	Solve	Easy	Adobe+33	Bit Manipulation Dynamic Programming
342. Power of Four	Solve	Easy	Adobe+4	Bit Manipulation Math+1
344. Reverse String	Solve	Easy	Adobe+6	String Two Pointers
345. Reverse Vowels of a String	Solve	Easy	Bloomberg	String Two Pointers
346. Moving Average from Data Stream	Solve	Easy	Amazon+3	Array Data Stream+2
349. Intersection of Two Arrays	Solve	Easy	Adobe+7	Array Binary Search+3
350. Intersection of Two Arrays II	Solve	Easy	Adobe+4	Array Binary Search+3
359. Logger Rate Limiter	Solve	Easy	Amazon+5	Data Stream Design+1
367. Valid Perfect Square	Solve	Easy	Google+1	Binary Search Math
374. Guess Number Higher or Lower	Solve	Easy	Adobe+1	Binary Search Interactive
383. Ransom Note	Solve	Easy	Adobe+3	Counting Hash Table+1
387. First Unique Character in a String	Solve	Easy	Amazon+8	Counting Hash Table+2
389. Find the Difference	Solve	Easy	Adobe+4	Bit Manipulation Hash Table+2
392. Is Subsequence	Solve	Easy	Accolite+15	Dynamic Programming String+1
401. Binary Watch	Solve	Easy	Google	Backtracking Bit Manipulation
404. Sum of Left Leaves	Solve	Easy	Adobe+6	Binary Tree Breadth-First Search+2
405. Convert a Number to Hexadecimal	Solve	Easy	Amazon+1	Bit Manipulation Math
408. Valid Word Abbreviation	Solve	Easy	Facebook+1	String Two Pointers
409. Longest Palindrome	Solve	Easy	Amazon	Greedy Hash Table+1
412. Fizz Buzz	Solve	Easy	Apple+2	Math Simulation+1