Snowflake LeetCode Questions
100 questions all-time · 13 easy · 67 medium · 20 hard
| # | Problem | Difficulty | Frequency | Acceptance |
|---|---|---|---|---|
| 1 | Happy Number Hash Table, Math, Two Pointers | Easy | 100 | 0.6% |
| 2 | Course Schedule II Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort | Medium | 96 | 0.6% |
| 3 | Design In-Memory File System Hash Table, String, Design, Trie, Sorting | Hard | 93 | 0.5% |
| 4 | Parallel Courses III Array, Dynamic Programming, Graph Theory, Topological Sort | Hard | 93 | 0.7% |
| 5 | Minimum Window Substring Hash Table, String, Sliding Window | Hard | 91 | 0.5% |
| 6 | Word Search II Array, String, Backtracking, Trie, Matrix | Hard | 90 | 0.4% |
| 7 | Trapping Rain Water Array, Two Pointers, Dynamic Programming, Stack, Monotonic Stack | Hard | 86 | 0.7% |
| 8 | Painting the Walls Array, Dynamic Programming | Hard | 85 | 0.5% |
| 9 | Throne Inheritance Hash Table, Tree, Depth-First Search, Design | Medium | 84 | 0.7% |
| 10 | Calculate Amount Paid in Taxes Array, Simulation | Easy | 82 | 0.7% |
| 11 | Step-By-Step Directions From a Binary Tree Node to Another String, Tree, Depth-First Search, Binary Tree | Medium | 82 | 0.6% |
| 12 | Maximum Number of Upgradable Servers Array, Math, Binary Search | Medium | 81 | 0.4% |
| 13 | Find All Anagrams in a String Hash Table, String, Sliding Window | Medium | 81 | 0.5% |
| 14 | Maximum Profit in Job Scheduling Array, Binary Search, Dynamic Programming, Sorting | Hard | 79 | 0.5% |
| 15 | Count Vowel Substrings of a String Hash Table, String | Easy | 77 | 0.7% |
| 16 | Minimum Array Length After Pair Removals Array, Hash Table, Two Pointers, Binary Search, Greedy, Counting | Medium | 75 | 0.3% |
| 17 | Find the Maximum Length of a Good Subsequence I Array, Hash Table, Dynamic Programming | Medium | 75 | 0.3% |
| 18 | String Transformation Math, String, Dynamic Programming, String Matching | Hard | 75 | 0.3% |
| 19 | Find the Maximum Length of a Good Subsequence II Array, Hash Table, Dynamic Programming | Hard | 73 | 0.3% |
| 20 | Number of Ways to Form a Target String Given a Dictionary Array, String, Dynamic Programming | Hard | 71 | 0.6% |
| 21 | Merge k Sorted Lists Linked List, Divide and Conquer, Heap (Priority Queue), Merge Sort | Hard | 71 | 0.6% |
| 22 | Course Schedule Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort | Medium | 68 | 0.5% |
| 23 | Parallel Courses Graph Theory, Topological Sort | Medium | 68 | 0.6% |
| 24 | Minimum Absolute Difference Between Two Values Array, Enumeration | Easy | 68 | 0.7% |
| 25 | Design HashMap Array, Hash Table, Linked List, Design, Hash Function | Easy | 65 | 0.7% |
| 26 | Max Area of Island Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix | Medium | 65 | 0.7% |
| 27 | Two Sum Array, Hash Table | Easy | 65 | 0.6% |
| 28 | Boundary of Binary Tree Tree, Depth-First Search, Binary Tree | Medium | 62 | 0.5% |
| 29 | Basic Calculator Math, String, Stack, Recursion | Hard | 62 | 0.5% |
| 30 | Maximum Number of Events That Can Be Attended Array, Greedy, Sorting, Heap (Priority Queue) | Medium | 62 | 0.4% |
| 31 | Simplify Path String, Stack | Medium | 62 | 0.5% |
| 32 | Top K Frequent Elements Array, Hash Table, Divide and Conquer, Sorting, Heap (Priority Queue), Bucket Sort, Counting, Quickselect | Medium | 62 | 0.7% |
| 33 | Shortest Word Distance Array, String | Easy | 62 | 0.7% |
| 34 | Merge Two Sorted Lists Linked List, Recursion | Easy | 58 | 0.7% |
| 35 | Time Based Key-Value Store Hash Table, String, Binary Search, Design | Medium | 58 | 0.5% |
| 36 | LRU Cache Hash Table, Linked List, Design, Doubly-Linked List | Medium | 58 | 0.5% |
| 37 | Design Hit Counter Array, Binary Search, Design, Queue, Data Stream | Medium | 58 | 0.7% |
| 38 | Task Scheduler Array, Hash Table, Greedy, Sorting, Heap (Priority Queue), Counting | Medium | 58 | 0.6% |
| 39 | Copy List with Random Pointer Hash Table, Linked List | Medium | 58 | 0.6% |
| 40 | Maximize Distance to Closest Person Array | Medium | 58 | 0.5% |
| 41 | Design Add and Search Words Data Structure String, Depth-First Search, Design, Trie | Medium | 58 | 0.5% |
| 42 | Remove Sub-Folders from the Filesystem Array, String, Depth-First Search, Trie | Medium | 58 | 0.8% |
| 43 | Web Crawler Multithreaded Depth-First Search, Breadth-First Search, Concurrency | Medium | 58 | 0.5% |
| 44 | Web Crawler String, Depth-First Search, Breadth-First Search, Interactive | Medium | 58 | 0.7% |
| 45 | Regular Expression Matching String, Dynamic Programming, Recursion | Hard | 53 | 0.3% |
| 46 | Insert Delete GetRandom O(1) Array, Hash Table, Math, Design, Randomized | Medium | 53 | 0.6% |
| 47 | Min Stack Stack, Design | Medium | 53 | 0.6% |
| 48 | Snapshot Array Array, Hash Table, Binary Search, Design | Medium | 53 | 0.4% |
| 49 | Single Element in a Sorted Array Array, Binary Search | Medium | 53 | 0.6% |
| 50 | Keys and Rooms Depth-First Search, Breadth-First Search, Graph Theory | Medium | 53 | 0.8% |
| 51 | Maximum Number of Events That Can Be Attended II Array, Binary Search, Dynamic Programming, Sorting | Hard | 53 | 0.6% |
| 52 | Design Log Storage System Hash Table, String, Design, Ordered Set | Medium | 53 | 0.6% |
| 53 | Populating Next Right Pointers in Each Node Linked List, Tree, Depth-First Search, Breadth-First Search, Binary Tree | Medium | 46 | 0.7% |
| 54 | Integer to English Words Math, String, Recursion | Hard | 46 | 0.4% |
| 55 | Cheapest Flights Within K Stops Dynamic Programming, Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Shortest Path | Medium | 46 | 0.4% |
| 56 | Leaf-Similar Trees Tree, Depth-First Search, Binary Tree | Easy | 46 | 0.7% |
| 57 | Random Pick with Weight Array, Math, Binary Search, Prefix Sum, Randomized | Medium | 46 | 0.5% |
| 58 | Longest Univalue Path Tree, Depth-First Search, Binary Tree | Medium | 46 | 0.4% |
| 59 | Roman to Integer Hash Table, Math, String | Easy | 46 | 0.7% |
| 60 | Making A Large Island Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix | Hard | 46 | 0.6% |
| 61 | Reverse Only Letters Two Pointers, String | Easy | 46 | 0.7% |
| 62 | Most Stones Removed with Same Row or Column Hash Table, Depth-First Search, Union-Find, Graph Theory | Medium | 46 | 0.6% |
| 63 | Rotting Oranges Array, Breadth-First Search, Matrix | Medium | 46 | 0.6% |
| 64 | Parallel Courses II Dynamic Programming, Bit Manipulation, Graph Theory, Bitmask | Hard | 46 | 0.3% |
| 65 | Campus Bikes Array, Sorting, Heap (Priority Queue) | Medium | 46 | 0.6% |
| 66 | Graph Valid Tree Depth-First Search, Breadth-First Search, Union-Find, Graph Theory | Medium | 46 | 0.5% |
| 67 | Design Circular Deque Array, Linked List, Design, Queue | Medium | 46 | 0.6% |
| 68 | Most Frequent IDs Array, Hash Table, Heap (Priority Queue), Ordered Set | Medium | 46 | 0.4% |
| 69 | Populating Next Right Pointers in Each Node II Linked List, Tree, Depth-First Search, Breadth-First Search, Binary Tree | Medium | 37 | 0.6% |
| 70 | Basic Calculator II Math, String, Stack | Medium | 37 | 0.5% |
| 71 | Meeting Rooms II Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum | Medium | 37 | 0.5% |
| 72 | Encode and Decode Strings Array, String, Design | Medium | 37 | 0.5% |
| 73 | Maximum Number of Removable Characters Array, Two Pointers, String, Binary Search | Medium | 37 | 0.5% |
| 74 | Count Nodes Equal to Average of Subtree Tree, Depth-First Search, Binary Tree | Medium | 37 | 0.9% |
| 75 | Container With Most Water Array, Two Pointers, Greedy | Medium | 37 | 0.6% |
| 76 | Find Median from Data Stream Two Pointers, Design, Sorting, Heap (Priority Queue), Data Stream | Hard | 37 | 0.5% |
| 77 | Construct Binary Tree from Preorder and Inorder Traversal Array, Hash Table, Divide and Conquer, Tree, Binary Tree | Medium | 37 | 0.7% |
| 78 | Most Profitable Path in a Tree Array, Tree, Depth-First Search, Breadth-First Search, Graph Theory | Medium | 37 | 0.7% |
| 79 | N-Queens II Backtracking | Hard | 37 | 0.8% |
| 80 | Valid Word Abbreviation Two Pointers, String | Easy | 37 | 0.4% |
| 81 | Implement Trie (Prefix Tree) Hash Table, String, Design, Trie | Medium | 37 | 0.7% |
| 82 | Walls and Gates Array, Breadth-First Search, Matrix | Medium | 37 | 0.6% |
| 83 | Path With Minimum Effort Array, Binary Search, Depth-First Search, Breadth-First Search, Union-Find, Heap (Priority Queue), Matrix | Medium | 37 | 0.6% |
| 84 | Remove K Digits String, Stack, Greedy, Monotonic Stack | Medium | 37 | 0.4% |
| 85 | Best Time to Buy and Sell Stock Array, Dynamic Programming | Easy | 37 | 0.6% |
| 86 | Non-overlapping Intervals Array, Dynamic Programming, Greedy, Sorting | Medium | 37 | 0.6% |
| 87 | Boats to Save People Array, Two Pointers, Greedy, Sorting | Medium | 37 | 0.6% |
| 88 | Word Search Array, String, Backtracking, Depth-First Search, Matrix | Medium | 37 | 0.5% |
| 89 | My Calendar I Array, Binary Search, Design, Segment Tree, Ordered Set | Medium | 37 | 0.6% |
| 90 | Alert Using Same Key-Card Three or More Times in a One Hour Period Array, Hash Table, String, Sorting | Medium | 37 | 0.5% |
| 91 | Design Circular Queue Array, Linked List, Design, Queue | Medium | 37 | 0.5% |
| 92 | Design File System Hash Table, String, Design, Trie | Medium | 37 | 0.7% |
| 93 | Paint Fence Dynamic Programming | Medium | 37 | 0.5% |
| 94 | Add Two Numbers Linked List, Math, Recursion | Medium | 37 | 0.5% |
| 95 | Jump Game II Array, Dynamic Programming, Greedy | Medium | 37 | 0.4% |
| 96 | The Maze Array, Depth-First Search, Breadth-First Search, Matrix | Medium | 37 | 0.6% |
| 97 | Height of Binary Tree After Subtree Removal Queries Array, Tree, Depth-First Search, Breadth-First Search, Binary Tree | Hard | 37 | 0.5% |
| 98 | Design Browser History Array, Linked List, Stack, Design, Doubly-Linked List, Data Stream | Medium | 37 | 0.8% |
| 99 | Number of Islands Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix | Medium | 37 | 0.6% |
| 100 | Possible Bipartition Depth-First Search, Breadth-First Search, Union-Find, Graph Theory | Medium | 37 | 0.5% |
How to read this list
The tabs at the top split the questions by how recently people said they were asked in interviews. "Last 30 Days" is the past month, "Last 3 Months" is the past quarter, and so on. "All Time" is every question on record for this company.
Frequency is a score from 0 to 100 for how often a question showed up in that time window. A higher number means it came up more often, so the list starts with the most common questions first. Acceptance is the share of submissions that pass on LeetCode. Click any question to open it on LeetCode.