Filter and Map for UI Data

The Times of India homepage receives article objects from multiple feed sources. Prepare a UI-ready list of article cards by filtering eligible articles, removing duplicate IDs, ranking the remaining articles, and selecting a maximum number of results.

Implement prepare_feed(items, category, min_score, limit).

Requirements

1. Keep only articles where isPublished is True, category matches the requested category, and score is at least min_score.
2. If an article ID appears more than once, keep the occurrence with the highest score. If scores are equal, keep the earliest occurrence.
3. Sort retained articles by descending score. Preserve original input order when scores are equal.
4. Return at most limit objects, mapped to only these fields: id, title, imageUrl, and score.
5. Do not mutate the input array or its objects. Return an empty array when no article qualifies.

Formal Specification

Input is an array of objects with fields id and title as strings, category as a string, isPublished as a boolean, score as an integer, and imageUrl as a string. category is a string, min_score is an integer, and limit is a non-negative integer. Return an array of mapped objects in ranked order.

Examples

Example 1: items = [{id: "a", title: "A", category: "sports", isPublished: true, score: 80, imageUrl: "a.jpg"}, {id: "b", title: "B", category: "sports", isPublished: true, score: 95, imageUrl: "b.jpg"}], category = "sports", min_score = 70, limit = 2 returns [{id: "b", title: "B", imageUrl: "b.jpg", score: 95}, {id: "a", title: "A", imageUrl: "a.jpg", score: 80}].

Example 2: Duplicate IDs retain the higher-scoring article, while unpublished or mismatched articles are excluded.

Constraints

• 1 <= items.length <= 10^5
• 0 <= limit <= items.length
• Scores are between 0 and 10^9.