Queue LeetCode Problems: All 43, With Python Solutions
Every problem in this library that LeetCode tags Queue — 43 in total, 34 of them with a complete Python solution, a worked example and the time and space complexity of the approach.
- 43 problems
- 7 Easy
- 19 Medium
- 17 Hard
How Queue problems are solved
A tag names the subject, not the method. These pattern hubs cover the techniques that actually solve Queue problems — each one explains the approach, gives a Python template and states its complexity.
- Stack — When the most recent unresolved thing is the one that matters, use a stack.
Queue problems by difficulty
Problems with a complete Python solution are listed first, then by ascending problem number.
Easy (7)
| # | Problem | Difficulty | Topics |
|---|---|---|---|
| 225 | Implement Stack using Queues | Easy | Stack, Design, Queue |
| 232 | Implement Queue using Stacks | Easy | Stack, Design, Queue |
| 387 | First Unique Character in a String | Easy | Queue, Hash Table, String +1 |
| 933 | Number of Recent Calls | Easy | Design, Queue, Data Stream |
| 1700 | Number of Students Unable to Eat Lunch | Easy | Stack, Queue, Array +1 |
| 2073 | Time Needed to Buy Tickets | Easy | Queue, Array, Simulation |
| 346 | Moving Average from Data StreamPremium | Easy | Design, Queue, Array +1 |
Medium (19)
| # | Problem | Difficulty | Topics |
|---|---|---|---|
| 341 | Flatten Nested List Iterator | Medium | Stack, Tree, Depth-First Search +3 |
| 622 | Design Circular Queue | Medium | Design, Queue, Array +1 |
| 641 | Design Circular Deque | Medium | Design, Queue, Array +1 |
| 649 | Dota2 Senate | Medium | Greedy, Queue, String |
| 918 | Maximum Sum Circular Subarray | Medium | Queue, Array, Divide and Conquer +2 |
| 950 | Reveal Cards In Increasing Order | Medium | Queue, Array, Sorting +1 |
| 1438 | Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit | Medium | Queue, Array, Ordered Set +3 |
| 1670 | Design Front Middle Back Queue | Medium | Design, Queue, Array +2 |
| 1696 | Jump Game VI | Medium | Queue, Array, Dynamic Programming +2 |
| 1823 | Find the Winner of the Circular Game | Medium | Recursion, Queue, Array +2 |
| 2327 | Number of People Aware of a Secret | Medium | Queue, Dynamic Programming, Simulation |
| 2526 | Find Consecutive Integers from a Data Stream | Medium | Design, Queue, Hash Table +2 |
| 2762 | Continuous Subarrays | Medium | Queue, Array, Ordered Set +3 |
| 2944 | Minimum Number of Coins for Fruits | Medium | Queue, Array, Dynamic Programming +2 |
| 281 | Zigzag IteratorPremium | Medium | Design, Queue, Array +1 |
| 353 | Design Snake GamePremium | Medium | Design, Queue, Array +2 |
| 362 | Design Hit CounterPremium | Medium | Design, Queue, Array +2 |
| 379 | Design Phone DirectoryPremium | Medium | Design, Queue, Array +2 |
| 1429 | First Unique NumberPremium | Medium | Design, Queue, Array +2 |
Hard (17)
| # | Problem | Difficulty | Topics |
|---|---|---|---|
| 239 | Sliding Window Maximum | Hard | Queue, Array, Sliding Window +2 |
| 862 | Shortest Subarray with Sum at Least K | Hard | Queue, Array, Binary Search +4 |
| 936 | Stamping The Sequence | Hard | Stack, Greedy, Queue +1 |
| 995 | Minimum Number of K Consecutive Bit Flips | Hard | Bit Manipulation, Queue, Array +2 |
| 1425 | Constrained Subsequence Sum | Hard | Queue, Array, Dynamic Programming +3 |
| 1499 | Max Value of Equation | Hard | Queue, Array, Sliding Window +2 |
| 1687 | Delivering Boxes from Storage to Ports | Hard | Segment Tree, Queue, Array +4 |
| 1825 | Finding MK Average | Hard | Design, Queue, Data Stream +2 |
| 2071 | Maximum Number of Tasks You Can Assign | Hard | Greedy, Queue, Array +4 |
| 2398 | Maximum Number of Robots Within Budget | Hard | Queue, Array, Binary Search +4 |
| 2407 | Longest Increasing Subsequence II | Hard | Binary Indexed Tree, Segment Tree, Queue +4 |
| 2444 | Count Subarrays With Fixed Bounds | Hard | Queue, Array, Sliding Window +1 |
| 2528 | Maximize the Minimum Powered City | Hard | Greedy, Queue, Array +3 |
| 2945 | Find Maximum Non-decreasing Array Length | Hard | Stack, Queue, Array +4 |
| 683 | K Empty SlotsPremium | Hard | Binary Indexed Tree, Segment Tree, Queue +5 |
| 2534 | Time Taken to Cross the DoorPremium | Hard | Queue, Array, Simulation |
| 2969 | Minimum Number of Coins for Fruits IIPremium | Hard | Queue, Array, Dynamic Programming +2 |
Keep exploring
All LeetCode topicsEvery tag with a page of its own, with the number of problems behind each.LeetCode patternsThe techniques themselves, with a Python template and complexity for each.Curated study listsBlind 75, NeetCode 150 and three more, grouped by pattern.Easy problemsStart here when the data structure is new rather than the problem.
Other topics
- Array1,569
- String672
- Hash Table588
- Math485
- Dynamic Programming481
- Sorting392
- Greedy346
- Depth-First Search289
- Binary Search253
- Database249
- Tree225
- Breadth-First Search223
- Matrix216
- Two Pointers201
- Bit Manipulation194
- Binary Tree174
- Heap (Priority Queue)163
- Prefix Sum157
- Stack157
- Simulation144
- Graph138
- Counting126
- Design122
- Sliding Window116
When the Queue problem arrives live
Stealth Interview is a desktop app for macOS and Windows. It reads the coding problem off your screen, returns a working solution with a step-by-step explanation and its time and space complexity, and transcribes what the interviewer is saying — while staying invisible to screen sharing.