Queue Study Guide ================= :::warning [< Return to Home Page](https://hackmd.io/@siansiansu/HknJJm0W0) ::: Basic Queue Operations ---------------------- ### Simple Queue Implementation and usage of a basic queue structure. - 🟨 [362\. Design Hit Counter](https://leetcode.com/problems/design-hit-counter/) ### Circular Queue Implementation of a queue with a fixed size that wraps around. - 🟨 [622\. Design Circular Queue](https://leetcode.com/problems/design-circular-queue/) Advanced Queue Types -------------------- ### Double-ended Queue (Deque) A queue that allows insertion and deletion at both ends. - 🟥 [239\. Sliding Window Maximum](https://leetcode.com/problems/sliding-window-maximum/) ### Priority Queue (Heap) A queue where elements have associated priorities. - 🟥 [23\. Merge k Sorted Lists](https://leetcode.com/problems/merge-k-sorted-lists/) - 🟨 [215\. Kth Largest Element in an Array](https://leetcode.com/problems/kth-largest-element-in-an-array/) \[[Solution](https://hackmd.io/@siansiansu/Hy8sIAF7A)\] - 🟥 [295\. Find Median from Data Stream](https://leetcode.com/problems/find-median-from-data-stream/) - 🟨 [973\. K Closest Points to Origin](https://leetcode.com/problems/k-closest-points-to-origin/) Queue-based Problems -------------------- ### Top K Problems Problems involving finding the K most frequent or largest elements. - 🟨 [347\. Top K Frequent Elements](https://leetcode.com/problems/top-k-frequent-elements/) \[[Solution](https://hackmd.io/@siansiansu/ByKpMm9mC)\] - 🟨 [692\. Top K Frequent Words](https://leetcode.com/problems/top-k-frequent-words/) \[[Solution](https://hackmd.io/@siansiansu/HyKBZB9mR)\] - 🟨 [658\. Find K Closest Elements](https://leetcode.com/problems/find-k-closest-elements/) \[[Solution](https://hackmd.io/@siansiansu/By0i_M9m0)\] ### Interval Problems Problems involving overlapping intervals or ranges. - 🟥 [759\. Employee Free Time](https://leetcode.com/problems/employee-free-time/) - 🟥 [632\. Smallest Range Covering Elements from K Lists](https://leetcode.com/problems/smallest-range-covering-elements-from-k-lists/) ### Task Scheduling Problems involving scheduling or organizing tasks. - 🟨 [621\. Task Scheduler](https://leetcode.com/problems/task-scheduler/) \[Solution\] Problem Difficulty Legend ------------------------- - 🟩 Easy - 🟨 Medium - 🟧 Medium-Hard - 🟥 Hard - ⬛ Very Hard Additional Resources -------------------- - [Queue Data Structure (Video)](https://www.youtube.com/watch?v=wjI1WNcIntg) - [Priority Queue and Heap Explained](https://www.geeksforgeeks.org/priority-queue-set-1-introduction/) - [Deque in Python](https://docs.python.org/3/library/collections.html#collections.deque)