Design a Todo Application | Dataford Interview Questions

Design and implement a Todo application, starting with the data model and then building the application.

Asked in the Round 2 stage.

Represent each Todo as a dictionary with id, title, and completed fields. Implement build_todo_app(operations), which processes valid operations in order and returns the final Todo list. Supported operations are add, update, toggle, and delete. Ignore operations targeting an unknown ID. Preserve insertion order and return each Todo as { "id": integer, "title": string, "completed": boolean }.

Input and Output

operations is a list of operation dictionaries. Return the final list of Todo dictionaries.

Constraints

0 <= operations.length <= 1000
Each operation has one of the actions: add, update, toggle, or delete
Todo IDs are integers
Titles are non-empty strings
Add operations use unique IDs
Operations targeting unknown IDs must be ignored

Function Signature

def build_todo_app(operations):

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