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
261. Graph Valid Tree	Solve	Medium	Amazon+3	Breadth-First Search Depth-First Search+2
264. Ugly Number II	Solve	Medium	Microsoft	Dynamic Programming Hash Table+2
267. Palindrome Permutation II	Solve	Medium	Cruise Automation+1	Backtracking Hash Table+1
271. Encode and Decode Strings	Solve	Medium	Facebook+1	Array Design+1
274. H-Index	Solve	Medium	Alation+4	Array Counting Sort+1
275. H-Index II	Solve	Medium	Goldman Sachs	Array Binary Search
276. Paint Fence	Solve	Medium	Google+1	Dynamic Programming
277. Find the Celebrity	Solve	Medium	Amazon+5	Graph Interactive+1
279. Perfect Squares	Solve	Medium	Amazon+3	Breadth-First Search Dynamic Programming+1
280. Wiggle Sort	Solve	Medium	Amazon+2	Array Greedy+1
281. Zigzag Iterator	Solve	Medium	Amazon+3	Array Design+2
284. Peeking Iterator	Solve	Medium	Amazon+3	Array Design+1
285. Inorder Successor in BST	Solve	Medium	Adobe+3	Binary Search Tree Binary Tree+2
286. Walls and Gates	Solve	Medium	Amazon+6	Array Breadth-First Search+1
287. Find the Duplicate Number	Solve	Medium	Adobe+30	Array Binary Search+2
288. Unique Word Abbreviation	Solve	Medium	Facebook+1	Array Design+2
289. Game of Life	Solve	Medium	Adobe+8	Array Matrix+1
291. Word Pattern II	Solve	Medium	Bolt+2	Backtracking Hash Table+1
294. Flip Game II	Solve	Medium	Google	Backtracking Dynamic Programming+3
298. Binary Tree Longest Consecutive Sequence	Solve	Medium	Amazon+2	Binary Tree Depth-First Search+1
299. Bulls and Cows	Solve	Medium	Facebook+1	Counting Hash Table+1
300. Longest Increasing Subsequence	Solve	Medium	Accenture+78	Array Binary Search+1
304. Range Sum Query 2D - Immutable	Solve	Medium	Amazon+4	Array Design+2
306. Additive Number	Solve	Medium	Booking.com+1	Backtracking String
307. Range Sum Query - Mutable	Solve	Medium	Amazon+1	Array Binary Indexed Tree+2
308. Range Sum Query 2D - Mutable	Solve	Medium	Google	Array Binary Indexed Tree+3
309. Best Time to Buy and Sell Stock with Cooldown	Solve	Medium	Adobe+5	Array Dynamic Programming
310. Minimum Height Trees	Solve	Medium	Amazon+1	Breadth-First Search Depth-First Search+2
311. Sparse Matrix Multiplication	Solve	Medium	Amazon+3	Array Hash Table+1
313. Super Ugly Number	Solve	Medium	Apple+2	Array Dynamic Programming+1
314. Binary Tree Vertical Order Traversal	Solve	Medium	Amazon+3	Binary Tree Breadth-First Search+4
316. Remove Duplicate Letters	Solve	Medium	Amazon+6	Greedy Monotonic Stack+2
318. Maximum Product of Word Lengths	Solve	Medium	Bloomberg	Array Bit Manipulation+1
319. Bulb Switcher	Solve	Medium	Apple+3	Brainteaser Math
320. Generalized Abbreviation	Solve	Medium	Google	Backtracking Bit Manipulation+1
322. Coin Change	Solve	Medium	Amazon+7	Array Breadth-First Search+1
323. Number of Connected Components in an Undirected Graph	Solve	Medium	Amazon+5	Breadth-First Search Depth-First Search+2
324. Wiggle Sort II	Solve	Medium	Adobe	Array Divide and Conquer+3
325. Maximum Size Subarray Sum Equals k	Solve	Medium	Amazon+1	Array Hash Table+1
328. Odd Even Linked List	Solve	Medium	Adobe+4	Linked List
331. Verify Preorder Serialization of a Binary Tree	Solve	Medium	Google	Binary Tree Stack+2
333. Largest BST Subtree	Solve	Medium	Cohesity+2	Binary Search Tree Binary Tree+3
334. Increasing Triplet Subsequence	Solve	Medium	Facebook+1	Array Greedy
337. House Robber III	Solve	Medium	Adobe+2	Binary Tree Depth-First Search+2
339. Nested List Weight Sum	Solve	Medium	Amazon+2	Breadth-First Search Depth-First Search
340. Longest Substring with At Most K Distinct Characters	Solve	Medium	Amazon+1	Hash Table Sliding Window+1
341. Flatten Nested List Iterator	Solve	Medium	Airbnb+10	Depth-First Search Design+4
343. Integer Break	Solve	Medium	Adobe+12	Dynamic Programming Math
347. Top K Frequent Elements	Solve	Medium	Adobe+9	Array Bucket Sort+6
348. Design Tic-Tac-Toe	Solve	Medium	Adobe+4	Array Design+3