Find the first 2 cities from the `cities` collection.

Problem Statement

<p>Find the first 2 <code>cities</code> from the <code>cities</code> collection.</p>

Examples

Input: cities collection: +-----+----------+------------+ | _id | name | population | +-----+----------+------------+ | 1 | Tokyo | 37400000 | | 2 | Delhi | 30290000 | | 3 | Shanghai | 27060000 | | 4 | London | 9000000 | +-----+----------+------------+

Output: +-----+-------+------------+ | _id | name | population | +-----+-------+------------+ | 1 | Tokyo | 37400000 | | 2 | Delhi | 30290000 | +-----+-------+------------+

Explanation: The query restricts and skips documents to return the specified subset.

Complexity

Time Complexity: -

Space Complexity: -

Hints

💡 Hint 1: Use db.<collection>.find(<filter>) to query the documents in the collection. 💡 Hint 2: Pass an empty object {} to retrieve all documents, or specify key-value pairs for exact matching. 💡 Hint 3: Chain .toArray() to resolve the MongoDB cursor into a JavaScript array: return db.<collection>.find(...).toArray();

Editorial & Approach

Problem Overview & Intuition

To solve "Limit Results", we query the MongoDB document store. The goal is to find the first 2 cities from the `cities` collection. 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) {
  return db.cities.find({}).limit(2).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.

Limit Results

Easy

Find the first 2 cities from the cities collection.

Example Scenarios

1Example 1

Input:

cities collection

_id	name	population
1	Tokyo	37400000
2	Delhi	30290000
3	Shanghai	27060000
4	London	9000000

Output:

_id	name	population
1	Tokyo	37400000
2	Delhi	30290000

Explanation:

The query restricts and skips documents to return the specified subset.

MongoDB Editor

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Query Results (JSON)

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