Interview prep
Interview problem lists
The two standard interview lists, with every problem linked back to a lesson here. A mark here and a mark on a lesson page are the same record.
0/75 solved
Arrays & Hashing
0/8 · Roadmap node- 217Contains Duplicate↗EasyHash TableBig-O NotationSorting Lower Bound
- 242Valid Anagram↗EasyHash Set / Map Patterns
- 1Two Sum↗EasyHash Set / Map PatternsBig-O NotationLinear Search
- 49Group Anagrams↗MediumHash Set / Map Patterns
- 347Top K Frequent Elements↗MediumHash Set / Map PatternsHuffman CodingTop-K Problems
- 238Product of Array Except Self↗MediumArray & Dynamic Array
- 271Encode and Decode Strings↗Premium, linked to a free mirrorMedium
- 128Longest Consecutive Sequence↗MediumHash Set / Map PatternsSorting Lower Bound
Two Pointers
0/3 · Roadmap node- 125Valid Palindrome↗EasyTwo Pointers
- 153Sum↗MediumTwo Pointers
- 11Container With Most Water↗MediumTwo Pointers
Sliding Window
0/4 · Roadmap nodeStack
0/1 · Roadmap node- 20Valid Parentheses↗EasyStack
Binary Search
0/2 · Roadmap nodeLinked List
0/6 · Roadmap node- 206Reverse Linked List↗EasyRecursionReverse Linked List
- 21Merge Two Sorted Lists↗EasyMerge Lists
- 143Reorder List↗MediumFast & Slow Pointers
- 19Remove Nth Node From End of List↗MediumFast & Slow PointersSingly Linked List
- 141Linked List Cycle↗EasyFast & Slow Pointers
- 23Merge K Sorted Lists↗HardBinary HeapMerge Lists
Trees
0/11 · Roadmap node- 226Invert Binary Tree↗EasyBinary Tree Basics
- 104Maximum Depth of Binary Tree↗EasyBinary Tree Basics
- 100Same Tree↗EasyBinary Tree Basics
- 572Subtree of Another Tree↗Easy
- 235Lowest Common Ancestor of a Binary Search Tree↗MediumBST
- 102Binary Tree Level Order Traversal↗MediumQueue & DequeTraversal
- 98Validate Binary Search Tree↗MediumBST
- 230Kth Smallest Element In a Bst↗MediumBST
- 105Construct Binary Tree From Preorder And Inorder Traversal↗MediumTraversal
- 124Binary Tree Maximum Path Sum↗HardTree DP
- 297Serialize And Deserialize Binary Tree↗HardTraversal
Tries
0/3 · Roadmap nodeHeap / Priority Queue
0/1 · Roadmap nodeBacktracking
0/2 · Roadmap nodeGraphs
0/6 · Roadmap node- 200Number of Islands↗MediumMatrixUnion-FindBFS
- 133Clone Graph↗MediumAdjacency List / MatrixDFS
- 417Pacific Atlantic Water Flow↗MediumGrid as Graph
- 207Course Schedule↗MediumCycle DetectionDFS
- 323Number of Connected Components In An Undirected Graph↗Premium, linked to a free mirrorMedium
- 261Graph Valid Tree↗Premium, linked to a free mirrorMedium
Advanced Graphs
0/1 · Roadmap node- 269Alien Dictionary↗Premium, linked to a free mirrorHard
1-D Dynamic Programming
0/10 · Roadmap node- 70Climbing Stairs↗EasyMemoization & TabulationRecursion
- 198House Robber↗Medium1-D DP
- 213House Robber II↗Medium1-D DP
- 5Longest Palindromic Substring↗MediumManacher
- 647Palindromic Substrings↗MediumManacher
- 91Decode Ways↗Medium1-D DP
- 322Coin Change↗MediumUnbounded KnapsackCoin Change (Greedy)
- 152Maximum Product Subarray↗MediumMaximum Subarray
- 139Word Break↗Medium1-D DPUnbounded Knapsack
- 300Longest Increasing Subsequence↗MediumLIS
2-D Dynamic Programming
0/2 · Roadmap node- 62Unique Paths↗MediumGrid DP
- 1143Longest Common Subsequence↗MediumLCS
Greedy
0/2 · Roadmap node- 53Maximum Subarray↗MediumMaximum Subarray
- 55Jump Game↗MediumJump Game
Intervals
0/5 · Roadmap node- 57Insert Interval↗MediumInsertion Sort
- 56Merge Intervals↗MediumInterval Scheduling
- 435Non Overlapping Intervals↗MediumInterval Scheduling
- 252Meeting Rooms↗Premium, linked to a free mirrorEasy
- 253Meeting Rooms II↗Premium, linked to a free mirrorMediumTwo Heaps
Math & Geometry
0/3 · Roadmap node- 48Rotate Image↗MediumMatrix
- 54Spiral Matrix↗MediumMatrix
- 73Set Matrix Zeroes↗MediumMatrix
Bit Manipulation
0/5 · Roadmap node- 191Number of 1 Bits↗EasyCounting Bits
- 338Counting Bits↗EasyCounting Bits
- 190Reverse Bits↗EasyBitwise Basics
- 268Missing Number↗EasyXOR Tricks
- 371Sum of Two Integers↗MediumBitwise Basics