Amazon
2015 problems
| Problem | Difficulty | Frequency ↓ | Topics |
|---|---|---|---|
| Lowest Common Ancestor of a Binary Tree | Medium | 70.4% | TopicsTreeDepth-First SearchBinary TreeBinary LiftingLowest Common Ancestor |
| 9. Palindrome Number | Easy | 70.2% | TopicsMath |
| 22. Generate Parentheses | Medium | 69.8% | TopicsStringDynamic ProgrammingBacktrackingBracket Sequences |
| 169. Majority Element | Easy | 69.4% | TopicsArrayHash TableDivide and ConquerSortingCountingBoyer–Moore Majority Vote Algorithm |
| 138. Copy List with Random Pointer | Medium | 68.9% | TopicsHash TableLinked List |
| 238. Product of Array Except Self | Medium | 67.6% | TopicsArrayPrefix Sum |
| 88. Merge Sorted Array | Easy | 67.4% | TopicsArrayTwo PointersSorting |
| 127. Word Ladder | Hard | 67.1% | TopicsHash TableStringBreadth-First SearchBidirectional Search |
| 198. House Robber | Medium | 67.1% | TopicsArrayDynamic Programming |
| 70. Climbing Stairs | Easy | 66.7% | TopicsMathDynamic ProgrammingMemoization |
| Sliding Window Maximum | Hard | 66.4% | TopicsArrayQueueSliding WindowHeap (Priority Queue)Monotonic QueueRange Minimum/Maximum Query |
| 21. Merge Two Sorted Lists | Easy | 66.3% | TopicsLinked ListRecursion |
| 17. Letter Combinations of a Phone Number | Medium | 65.7% | TopicsHash TableStringBacktracking |
| 55. Jump Game | Medium | 65.7% | TopicsArrayDynamic ProgrammingGreedy |
| 242. Valid Anagram | Easy | 65.4% | TopicsHash TableStringSorting |
| 904. Fruit Into Baskets | Medium | 65.1% | TopicsArrayHash TableSliding Window |
| 79. Word Search | Medium | 64.7% | TopicsArrayStringBacktrackingDepth-First SearchMatrix |
| 210. Course Schedule II | Medium | 64.7% | TopicsDepth-First SearchBreadth-First SearchGraph TheoryTopological Sort |
| 78. Subsets | Medium | 64.5% | TopicsArrayBacktrackingBit Manipulation |
| 54. Spiral Matrix | Medium | 64.4% | TopicsArrayMatrixSimulation |
| Remove Duplicates from Sorted Array | Easy | 64.2% | TopicsArrayTwo Pointers |
| Next Permutation | Medium | 64.2% | TopicsArrayTwo Pointers |
| 7. Reverse Integer | Medium | 63.4% | TopicsMath |
| 295. Find Median from Data Stream | Hard | 63.2% | TopicsTwo PointersDesignSortingHeap (Priority Queue)Data Stream |
| 322. Coin Change | Medium | 63.2% | TopicsArrayDynamic ProgrammingBreadth-First SearchKnapsack ProblemComplete Knapsack |
