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Solution: Time Based Key-Value Store

Explore the implementation of a time based key-value store that can save multiple values for the same key at different timestamps. Understand how to optimize retrieval using binary search for efficient lookup and how to handle cases when exact timestamps are not present. This lesson improves your ability to design and analyze custom data structures for scalable solutions.

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Statement

Implement a data structure that can store multiple values of the same key at different timestamps and retrieve the key’s value at a certain timestamp.

You’ll need to implement the TimeStamp class. This class has the following functions:

  • Init(): This function initializes the values dictionary and timestamp dictionary.

  • Set Value(key, value, timestamp): This function stores the key and value at any given timestamp.

  • Get Value(key, timestamp): This function returns the value set for this key at the specified timestamp.

Note: When a query requests the value of a key at a timestamp that isn’t recorded, return the value corresponding to the most recent timestamp before the query’s timestamp. If there are no timestamps before the query’s timestamp, return an empty string.

Constraints:

  • 1≤1 \leq key.length, value.length ≤20\leq 20
  • key and value consist of lowercase English letters and digits.
  • 1≤1 \leq timestamp ≤103
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