- Includes all Grind 169 questions.
- Includes Extra questions I like.
- TODO: Top Interview questions.
| Name | Complexity | Examples | Notes |
|---|---|---|---|
| Constant | O(1) |
Basic arithmetics | |
| Logarithmic | O(log n) |
Binary search, balanced tree height | |
| Linear | O(n) |
Linear search, non-comparison sort | |
| Linearithmic | O(n log n) |
Comparison sort | also known as Quasilinear |
| Quadratic | O(n^2) |
||
| Cubic | O(n^3) |
||
| Exponential | O(2^n) |
Backtracking (all subsets) | |
| Factorial | O(n!) |
Backtracking (all permutations) |
- Two Sum | 🟩
- Best Time to Buy and Sell Stock | 🟩
- Majority Element | 🟩
- Majority Element II | 🟨 | Extra
- Meeting Rooms | 🟩
- Meeting Rooms II | 🟨
- Contains Duplicate | 🟩
- Move Zeroes | 🟩
- Squares of a Sorted Array | 🟩
- Insert Interval | 🟨
- 3Sum | 🟨
- Product of Array Except Self | 🟨
- Merge Intervals | 🟨
- Sort Colors | 🟨
- Container With Most Water | 🟨
- Gas Station | 🟨
- Longest Consecutive Sequence | 🟨
- Rotate Array | 🟨
- Contiguous Array | 🟨
- Subarray Sum Equals K | 🟨
- 3Sum Closest | 🟨
- Non-overlapping Intervals | 🟨
- Employee Free Time | 🟥
- Sliding Window Maximum | 🟥
- Flood Fill | 🟩
- 01 Matrix | 🟨
- Clone Graph | 🟨
- Course Schedule | 🟨
- Number of Islands | 🟨
- Rotting Oranges | 🟨
- Accounts Merge | 🟨
- Word Search | 🟨
- Minimum Height Trees | 🟨
- Pacific Atlantic Water Flow | 🟨
- Shortest Path to Get Food | 🟨
- Graph Valid Tree | 🟨
- Course Schedule II | 🟨
- Number of Connected Components in an Undirected Graph | 🟨
- Minimum Knight Moves | 🟨
- Cheapest Flights Within K Stops | 🟨
- Word Ladder | 🟥
- Longest Increasing Path in a Matrix | 🟥
- Word Search II | 🟥
- Alien Dictionary | 🟥
- Bus Routes | 🟥
- Invert Binary Tree | 🟩
- Balanced Binary Tree | 🟩
- Diameter of Binary Tree | 🟩
- Maximum Depth of Binary Tree | 🟩
- Same Tree | 🟩
- Symmetric Tree | 🟩
- Subtree of Another Tree | 🟩
- Binary Tree Level Order Traversal | 🟨
- Lowest Common Ancestor of a Binary Tree | 🟨
- Binary Tree Right Side View | 🟨
- Construct Binary Tree from Preorder and Inorder Traversal | 🟨
- Construct Binary Tree from Inorder and Postorder Traversal | 🟨 | Extra
- Construct Binary Tree from Preorder and Postorder Traversal
- Path Sum | 🟩 | Extra
- Path Sum II | 🟨
- Path Sum III | 🟨
- Maximum Width of Binary Tree | 🟨
- Binary Tree Zigzag Level Order Traversal | 🟨
- All Nodes Distance K in Binary Tree | 🟨
- Serialize and Deserialize Binary Tree | 🟥
- Binary Tree Maximum Path Sum | 🟥
- Step-By-Step Directions From a Binary Tree Node to Another | 🟨 | Extra
- Lowest Common Ancestor of a Binary Search Tree | 🟩
- Convert Sorted Array to Binary Search Tree | 🟩
- Validate Binary Search Tree | 🟨
- Kth Smallest Element in a BST | 🟨
- Inorder Successor in BST | 🟨
- Binary Search | 🟩
- First Bad Version | 🟩
- Search in Rotated Sorted Array | 🟨
- Time Based Key-Value Store | 🟨
- Search a 2D Matrix | 🟨
- Find Minimum in Rotated Sorted Array | 🟨
- Maximum Profit in Job Scheduling | 🟥
- Median of Two Sorted Arrays | 🟥
- Valid Palindrome | 🟩
- Valid Anagram | 🟩
- Longest Palindrome | 🟩
- Longest Common Prefix | 🟩
- Verifying an Alien Dictionary | 🟩 | Extra
- Longest Substring Without Repeating Characters | 🟨
- String to Integer (atoi) | 🟨
- Longest Palindromic Substring | 🟨
- Find All Anagrams in a String | 🟨
- Group Anagrams | 🟨
- Longest Repeating Character Replacement | 🟨
- Largest Number | 🟨
- Encode and Decode Strings | 🟨
- Minimum Window Substring | 🟥
- Palindrome Pairs | 🟥
- Implement Trie (Prefix Tree) | 🟨
- Word Break | 🟨
- Design Add and Search Words Data Structure | 🟨
- Design In-Memory File System | 🟥
- Spiral Matrix | 🟨
- Valid Sudoku | 🟨
- Rotate Image | 🟨
- Set Matrix Zeroes | 🟨
- Sudoku Solver | 🟥
- Roman to Integer | 🟩
- Palindrome Number | 🟩
- Random Pick with Weight | 🟨
- Pow(x, n) | 🟨
- Reverse Integer | 🟨
- Add Binary | 🟩
- Counting Bits | 🟩
- Number of 1 Bits | 🟩
- Single Number | 🟩
- Missing Number | 🟩
- Reverse Bits | 🟩
- Find the Duplicate Number | 🟨
- Valid Parentheses | 🟩
- Remove Invalid Parentheses | 🟥 | Extra
- Implement Queue using Stacks | 🟩
- Backspace String Compare | 🟩
- Min Stack | 🟨
- Daily Temperatures | 🟨
- Decode String | 🟨
- Evaluate Reverse Polish Notation | 🟨
- Asteroid Collision | 🟨
- Trapping Rain Water | 🟥
- Basic Calculator | 🟥
- Basic Calculator II | 🟨
- Largest Rectangle in Histogram | 🟥
- Maximum Frequency Stack | 🟥
- Longest Valid Parentheses | 🟥
- K Closest Points to Origin | 🟨
- Task Scheduler | 🟨
- Top K Frequent Words | 🟨
- Find K Closest Elements | 🟨
- Kth Largest Element in an Array | 🟨
- Find Median from Data Stream | 🟥
- Merge k Sorted Lists | 🟥
- Smallest Range Covering Elements from K Lists | 🟥
- Any distinct subset of size K from a set of N elements is a valid combination.
- Any distinct element arrangement of size N from a set with N elements is a valid permutation.
- Permutations | 🟨
- Permutations II | 🟨 | Extra
- Next Permutation | 🟨
- Permutation Sequence | 🟥 | Extra
- Subsets | 🟨
- Subsets II | 🟨 | Extra
- Combination Sum | 🟨
- Combination Sum II | 🟨 | Extra
- Combination Sum III | 🟨 | Extra
- Combination Sum IIV | 🟨 | Extra
- Combinations | 🟨 | Extra
- Letter Case Permutation | 🟨 | Extra
- Letter Combinations of a Phone Number | 🟨
- Generate Parentheses | 🟨
- N-Queens | 🟥
- N-Queens II | 🟥 | Extra
- Merge Two Sorted Lists | 🟩
- Linked List Cycle | 🟩
- Linked List Cycle II | 🟨 | Extra
- Reverse Linked List | 🟩
- Middle of the Linked List | 🟩
- Palindrome Linked List | 🟩
- LRU Cache | 🟨
- Remove Nth Node From End of List | 🟨
- Swap Nodes in Pairs | 🟨
- Odd Even Linked List | 🟨
- Add Two Numbers | 🟨
- Sort List | 🟨
- Reorder List | 🟨
- Rotate List | 🟨
- Reverse Nodes in k-Group | 🟥
- Ransom Note | 🟩
- Remove Letter To Equalize Frequency | 🟩 | Extra
- Insert Delete GetRandom O(1) | 🟨
- First Missing Positive | 🟥
- Climbing Stairs | 🟩
- Maximum Subarray | 🟨
- Coin Change | 🟨
- Partition Equal Subset Sum | 🟨
- Unique Paths | 🟨
- House Robber | 🟨
- Maximum Product Subarray | 🟨
- Longest Increasing Subsequence | 🟨
- Jump Game | 🟨
- Maximal Square | 🟨
- Decode Ways | 🟨
- Combination Sum IV | 🟨