Google Coding Interview Questions
125 problems · 16 Easy 92 Medium 17 Hard
Google problems
Google is known for harder-than-average problems and interviewers who probe scalability with follow-ups. High-frequency patterns: binary search, dynamic programming, graphs, and hashing. Expect to discuss trade-offs and worst-case complexity in depth on every solution.
Sliding Window 9 problems
Two Pointers 6 problems
| 3Sum | Medium | ||
| Container With Most Water | Medium | ||
| Trapping Rain Water | Hard | ||
| Squares of a Sorted Array | Easy | ||
| Boats to Save People | Medium | ||
| Minimum Length of String After Deleting Similar Ends | Medium |
Binary Search 6 problems
| Binary Search | Easy | ||
| Find Peak Element | Medium | ||
| Time Based Key-Value Store | Medium | ||
| Search a 2D Matrix | Medium | ||
| Split Array Largest Sum | Hard | ||
| Median of Two Sorted Arrays | Hard |
Prefix Sum 2 problems
| Subarray Sum Equals K | Medium | ||
| Find Pivot Index | Easy |
Hash Map / Set 7 problems
| Two Sum | Easy | ||
| Top K Frequent Elements | Medium | ||
| Longest Consecutive Sequence | Medium | ||
| Contains Duplicate | Easy | ||
| LRU Cache | Medium | ||
| 4Sum II | Medium | ||
| Subarray Sum Divisible by K | Medium |
Stack 8 problems
| Valid Parentheses | Easy | ||
| Min Stack | Medium | ||
| Daily Temperatures | Medium | ||
| Decode String | Medium | ||
| Asteroid Collision | Medium | ||
| Remove K Digits | Medium | ||
| Car Fleet | Medium | ||
| Simplify Path | Medium |
Queue / BFS 7 problems
| Number of Islands | Medium | ||
| Rotting Oranges | Medium | ||
| Word Ladder | Hard | ||
| Shortest Path in Binary Matrix | Medium | ||
| Open the Lock | Medium | ||
| Minimum Genetic Mutation | Medium | ||
| Jump Game III | Medium |
Heap / Priority Queue 6 problems
| Kth Largest Element in an Array | Medium | ||
| Find Median from Data Stream | Hard | ||
| Merge K Sorted Lists | Hard | ||
| Reorganize String | Medium | ||
| Top K Frequent Words | Medium | ||
| Find K Pairs with Smallest Sums | Medium |
Linked List 5 problems
| Linked List Cycle | Easy | ||
| Add Two Numbers | Medium | ||
| Remove Nth Node From End of List | Medium | ||
| Copy List with Random Pointer | Medium | ||
| Reverse Nodes in k-Group | Hard |
Trees / DFS 5 problems
Graphs 9 problems
| Clone Graph | Medium | ||
| Pacific Atlantic Water Flow | Medium | ||
| Number of Connected Components in Undirected Graph | Medium | ||
| Surrounded Regions | Medium | ||
| Minimum Height Trees | Medium | ||
| Network Delay Time | Medium | ||
| Find Eventual Safe States | Medium | ||
| All Paths From Source to Target | Medium | ||
| Cheapest Flights Within K Stops | Medium |
Dynamic Programming 20 problems
| House Robber | Medium | ||
| Coin Change | Medium | ||
| Longest Increasing Subsequence | Medium | ||
| Longest Common Subsequence | Medium | ||
| Word Break | Medium | ||
| Edit Distance | Hard | ||
| Unique Paths | Medium | ||
| Min Cost Climbing Stairs | Easy | ||
| House Robber II | Medium | ||
| Target Sum | Medium | ||
| Best Time to Buy and Sell Stock | Easy | ||
| Longest Palindromic Substring | Medium | ||
| Best Time to Buy and Sell Stock with Cooldown | Medium | ||
| Maximum Product Subarray | Medium | ||
| Minimum Path Sum | Medium | ||
| Perfect Squares | Medium | ||
| Regular Expression Matching | Hard | ||
| Interleaving String | Medium | ||
| Best Time to Buy and Sell Stock with Transaction Fee | Medium | ||
| Integer Break | Medium |
Greedy 6 problems
| Jump Game II | Medium | ||
| Gas Station | Medium | ||
| Non-overlapping Intervals | Medium | ||
| Meeting Rooms II | Medium | ||
| Queue Reconstruction by Height | Medium | ||
| Candy | Hard |
Trie 3 problems
| Implement Trie (Prefix Tree) | Medium | ||
| Word Search II | Hard | ||
| Longest Word in Dictionary | Medium |
Union Find 5 problems
| Redundant Connection | Medium | ||
| Accounts Merge | Medium | ||
| Number of Provinces | Medium | ||
| Satisfiability of Equality Equations | Medium | ||
| Swim in Rising Water | Hard |
Monotonic Stack 4 problems
| Largest Rectangle in Histogram | Hard | ||
| Sum of Subarray Minimums | Medium | ||
| 132 Pattern | Medium | ||
| Remove Duplicate Letters | Medium |
Topological Sort 3 problems
| Course Schedule | Medium | ||
| Parallel Courses | Medium | ||
| Sequence Reconstruction | Medium |
Bit Manipulation 3 problems
| Counting Bits | Easy | ||
| Number of 1 Bits | Easy | ||
| Power of Two | Easy |
Intervals 4 problems
| Merge Intervals | Medium | ||
| Insert Interval | Medium | ||
| Minimum Interval to Include Each Query | Hard | ||
| Meeting Rooms | Easy |
Matrix 4 problems
| Spiral Matrix | Medium | ||
| Game of Life | Medium | ||
| Search a 2D Matrix II | Medium | ||
| Count Negative Numbers in a Sorted Matrix | Easy |
Backtracking 3 problems
| Letter Combinations of a Phone Number | Medium | ||
| Generate Parentheses | Medium | ||
| Palindrome Partitioning | Medium |