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Problem: All O`one Data Structure

Understand how to design and implement the AllOne data structure that efficiently manages string keys with their counts. Explore the combination of a doubly linked list and hash maps to achieve average constant-time updates and queries for incrementing, decrementing, and retrieving keys with max or min frequency.

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Statement

Design a data structure that stores string keys along with their frequencies and supports efficient updates and queries.

Implement the AllOne class:

  • AllOne() → Initializes the data structure.

  • inc(key) → Increases the count of key by 1. If the key does not exist, insert it with count 1.

  • dec(key) → Decreases the count of key by 1. If the count becomes 0, remove the key. It is guaranteed the key exists when dec is called.

  • getMaxKey() → Returns any key with the highest count. If empty, return "" ...