Increment the `views` of article with `_id: 1` by `1`. Return all articles.

Problem Statement

<p>Increment the <code>views</code> of article with <code>_id: 1</code> by <code>1</code>. Return all articles.</p>

Examples

Input: articles collection: +-----+------------------+-------+ | _id | title | views | +-----+------------------+-------+ | 1 | Intro to MongoDB | 100 | | 2 | Advanced Queries | 50 | +-----+------------------+-------+

Output: +-----+------------------+-------+ | _id | title | views | +-----+------------------+-------+ | 1 | Intro to MongoDB | 101 | | 2 | Advanced Queries | 50 | +-----+------------------+-------+

Explanation: The target document is modified according to the update operators and the updated document is returned.

Complexity

Time Complexity: -

Space Complexity: -

Hints

💡 Hint 1: Filter documents where a field matches any value in a list using the $in or $nin operator. 💡 Hint 2: Pass the query object to db.<collection>.find({ field: { $in: [val1, val2, ...] } }). 💡 Hint 3: Call .toArray() on the returned cursor so the function returns the array of matching documents.

Editorial & Approach

Problem Overview & Intuition

To solve "Increment a Field ($inc)", we query the MongoDB document store. The goal is to increment the `views` of article with `_id: 1` by `1`. return all articles. Using a targeted find query, the database engine filters and structures the BSON documents efficiently.

Step-by-Step Approach

Identify Target Collection: Access the collection through the db instance.
Construct Query / Pipeline: Build the query filter with appropriate comparison operators.
Resolve Cursor: Invoke .toArray() to transform the query cursor into the required array of documents.

Optimal Implementation (MongoDB)

function solve(db) {
  db.articles.updateOne({ _id: 1 }, { $inc: { views: 1 } });
  return db.articles.find({}).toArray();
}

Complexity Analysis

Time Complexity O(N) collection scan (O(log N) if index is present on filtered fields).

Space Complexity O(K) where K is the number of returned documents in memory.

Key Considerations & Edge Cases

Empty Collections: If no documents match, the query cleanly returns an empty array [].
Missing / NULL Fields: Missing fields in documents are handled safely without throwing runtime exceptions.
Type Coercion: BSON types (ObjectId, Numbers, Strings) are compared strictly according to MongoDB specifications.

Increment a Field ($inc)

Easy

Increment the views of article with _id: 1 by 1. Return all articles.

Example Scenarios

1Example 1

Input:

articles collection

_id	title	views
1	Intro to MongoDB	100
2	Advanced Queries	50

Output:

_id	title	views
1	Intro to MongoDB	101
2	Advanced Queries	50

Explanation:

The target document is modified according to the update operators and the updated document is returned.

MongoDB Editor

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Query Results (JSON)

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