Get page 3 (page size 2) of employees sorted by `name` alphabetically. That means skip 4, limit 2.
Problem Statement
Examples
Input: employees collection: +-----+---------+ | _id | name | +-----+---------+ | 1 | Alice | | 2 | Bob | | 3 | Charlie | | 4 | Dana | | 5 | Eve | | 6 | Frank | +-----+---------+
Output: +-----+-------+ | _id | name | +-----+-------+ | 5 | Eve | | 6 | Frank | +-----+-------+
Explanation: The collection documents are sorted according to the specified field order.
Complexity
Time Complexity: -
Space Complexity: -
Hints
Editorial & Approach
Problem Overview & Intuition
To solve "Sorted Pagination (Sort + Skip + Limit)", we query the MongoDB document store. The goal is to get page 3 (page size 2) of employees sorted by `name` alphabetically. that means skip 4, limit 2. 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
dbinstance. - 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.employees.find({}).sort({ name: 1 }).skip(4).limit(2).toArray();
}
Complexity Analysis
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.