Скачать или смотреть ✅Day16 | LeetCode 380. Insert Delete GetRandom O(1) |

🌟 Welcome to the Leetcode Daily Challenge Solution! 🚀

Solution:- https://github.com/shubh-2935/daily-s...

Let's break down the provided C++ solution for the RandomizedSet class step by step.


🎯 Problem Overview:
The goal is to implement a data structure that supports three operations—insert, remove, and getRandom—such that each operation works in average O(1) time complexity.


🚀 Algorithm Breakdown:


Initialization:


The class includes an unordered_map "set" to store the mapping between values and their indices in a vector.


The vector "v" is used to store the actual elements.
Insert Operation:


When inserting a new value:


Check if the value is already present in the set.
If not, push the value to the vector and update the set with the new index.
Return true if the value was successfully inserted, otherwise return false.
Remove Operation:
When removing a value:


Check if the value is present in the set.
If yes, swap the element with the last element in the vector to avoid shifting elements.
Update the set with the new index of the swapped element.
Erase the value from the set.
Return true if the value was successfully removed, otherwise return false.
GetRandom Operation:
Return a random element from the vector using rand() % v.size().
📊 Complexity Analysis:


Time Complexity:


Insert and Remove: O(1) on average due to unordered_map constant time complexity.
GetRandom: O(1) since accessing an element in a vector by index is constant time.
Space Complexity: O(N), where N is the number of unique elements stored in the data structure.
👍 Explanation:


The algorithm efficiently supports constant time insert, remove, and getRandom operations.


The use of unordered_map ensures quick lookups and updates.


The vector holds the elements in a contiguous memory space, allowing for random access.


The getRandom function utilizes the random index to provide equal probability for each element.
Feel free to explore and modify the solution to further enhance your understanding and coding skills! 🔗✨

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