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Implement Hash Map Operations

TikTokBackend Software Engineer · Onsite
MediumBackend Software EngineerOnsiteCoding & Algorithms

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Build a hash map behind a deterministic operation stream with insertion, replacement, lookup, removal, and missing-key behavior. The specification avoids built-in map storage and fixes return ordering and value bounds for a future portable console implementation.

Implement Hash Map Operations

Implement process_hash_map(operations) without using a built-in hash-map or dictionary type for storage.

Each operation is one of these strings:

  • "PUT key value": insert key with value, or replace the existing value.
  • "GET key": append the current value for key to the result, or append -1 when the key is absent.
  • "REMOVE key": remove key if present; otherwise do nothing.

Return all GET results in operation order. The explicit operation grammar is a pedagogical assumption for the source's named hash-map design task.

Function Contract

process_hash_map(operations: list[str]) -> list[int]

Constraints

  • 0 <= len(operations) <= 200000
  • 0 <= key <= 1000000
  • 0 <= value <= 10^9
  • -1 is reserved to represent a missing key and is never supplied as a value.
  • Every operation follows one of the three formats above.

Examples

Example 1

Input: ["PUT 1 8", "PUT 2 5", "GET 1", "GET 3", "PUT 2 9", "GET 2"]
Output: [8, -1, 9]

The second put for key 2 replaces its earlier value.

Example 2

Input: ["PUT 4 0", "REMOVE 4", "GET 4", "REMOVE 4", "PUT 4 7", "GET 4"]
Output: [-1, 7]

Removing a missing key is a no-op, and a later insertion of the same key succeeds.