LeetCode 380: Insert Delete GetRandom O(1) | Optimized JavaScript Solution Explained
In this video, I walk you through solving LeetCode 380: Insert Delete GetRandom O(1) using JavaScript.
We build a custom data structure using a Map and an array to ensure all operations — insert, remove, and getRandom — run in O(1) time.
🌟 What you’ll learn:
Why a combination of Map and array works
How to swap and pop efficiently during removals
Tips to avoid common pitfalls with indices
👉 This solution is clean, optimal, and easy to understand. Great for interviews and system design warmups!
Timestamps:
0:00 - Problem overview
2:30 - O(1) insert/remove with Map + Array explanation
4:20 - Code walkthrough
9:50 - Time & space complexity
🧠 Time Complexity:
insert(val): O(1)
remove(val): O(1)
getRandom(): O(1)
💻 Space Complexity: O(n) for storing n elements
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