Queue
13 problems · 10 with full explanations
1 Easy6 Medium2 Hard
Queues support FIFO (first-in, first-out) operations. In C#, Queue<T> provides O(1) enqueue/dequeue. Key patterns: BFS, sliding window maximum (deque), and task scheduling. A double-ended queue (LinkedList<T> or ArrayDeque) supports both front and back operations.
How to practice
To practice Queue problems effectively, start with the Easy problems listed below, trace through each solution on paper, then re-implement without looking. When you can recognise the queue pattern within 30 seconds of reading a new problem, move on to Medium difficulty. Use the related topic pages and our study guide for a structured progression.
Start here (Easy + explained)
All Queue problems
- 239.Sliding Window MaximumHard
- 641.Design Circular DequeUnknown
- 862.Shortest Subarray with Sum at Least KHard
- 995.Minimum Number of K Consecutive Bit FlipsUnknown
- 1352.Product of the Last K NumbersMedium
- 1438.Longest Continuous Subarray With Absolute Diff Less Than or Equal to LimitMedium
- 1700.Number of Students Unable to Eat LunchEasy
- 1823.Find the Winner of the Circular GameMedium
- 2762.Continuous SubarraysMedium
- 3191.Minimum Operations to Make Binary Array Elements Equal to One IMedium
- 3477.Fruits Into Baskets IIMedium
- 3479.Fruits Into Baskets IIIUnknown
- 3508.Implement RouterUnknown