darren987469

Segment Tree

Video: Heap - Heap Sort - Heapify - Priority Queues create a heap: O(nlogn) heapify: O(n) insertion: O(logn) deletion: O(logn)

Leetcode:

• hard, 1206. Design Skiplist

Leetcode:

• hard, 239. Sliding Window Maximum

Leetcode:

• hard, 84. Largest Rectangle in Histogram
• medium, 316. Remove Duplicate Letters
• medium, 402. Remove K Digits
• medium, 946. Validate Stack Sequences
• medium, 1081. Smallest Subsequence of Distinct Characters

Leetcode:

• medium, 382. Linked List Random Node

Leetcode:

• medium, 146. LRU Cache

Leetcode:

• medium, 208.Implement Trie (Prefix Tree)

Leetcode:

• medium, 78. Subsets
• medium, 90. subsets II

Scenario: User can use discount_code to get a discount. System records the discount_code_usage every time the user uses. Please write a query to find total usage and this month usage of discount codes of the user.