Recyclable and Low Fat Products - Practice Coding Problems

Recyclable and Low Fat Products - Problem

Database Easy

🌱 Recyclable and Low Fat Products

You're working as a data analyst for a health-conscious grocery store chain that wants to promote environmentally friendly and healthy products. The store has a comprehensive database of all products with their nutritional and environmental attributes.

Given a Products table with the following structure:

Column Name	Type
product_id	int
low_fats	enum ('Y', 'N')
recyclable	enum ('Y', 'N')

Where:

product_id is the unique identifier for each product
low_fats indicates if the product is low in fat ('Y' = Yes, 'N' = No)
recyclable indicates if the product packaging is recyclable ('Y' = Yes, 'N' = No)

Your mission: Find all products that are both low fat and recyclable to feature in the store's new "Healthy & Green" promotion campaign.

Return the product IDs in any order.

Input & Output

Basic Example - Mixed Product Types

$ Input: Products table: +-------------+----------+------------+ | product_id | low_fats | recyclable | +-------------+----------+------------+ | 0 | Y | N | | 1 | Y | Y | | 2 | N | Y | | 3 | Y | Y | | 4 | N | N | +-------------+----------+------------+

› Output: +-------------+ | product_id | +-------------+ | 1 | | 3 | +-------------+

💡 Note: Products 1 and 3 are the only ones that satisfy both conditions: low_fats = 'Y' AND recyclable = 'Y'. Product 0 is low fat but not recyclable, Product 2 is recyclable but not low fat, and Product 4 satisfies neither condition.

All Products Qualify

$ Input: Products table: +-------------+----------+------------+ | product_id | low_fats | recyclable | +-------------+----------+------------+ | 10 | Y | Y | | 20 | Y | Y | | 30 | Y | Y | +-------------+----------+------------+

› Output: +-------------+ | product_id | +-------------+ | 10 | | 20 | | 30 | +-------------+

💡 Note: All products in this healthy store satisfy both conditions, so all product IDs are returned.

No Products Qualify

$ Input: Products table: +-------------+----------+------------+ | product_id | low_fats | recyclable | +-------------+----------+------------+ | 100 | N | N | | 101 | Y | N | | 102 | N | Y | +-------------+----------+------------+

› Output: +-------------+ | product_id | +-------------+ +-------------+

💡 Note: No products satisfy both conditions simultaneously. Product 101 is low fat but not recyclable, Product 102 is recyclable but not low fat, and Product 100 satisfies neither condition. The result is an empty set.

Constraints

1 ≤ Number of rows in Products table ≤ 1000
product_id is unique for each row
low_fats and recyclable are ENUM types with values ('Y', 'N')
All ENUM values are guaranteed to be either 'Y' or 'N'

Visualization

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Understanding the Visualization

Products Enter Scanner

Each product passes through a dual-sensor scanner that checks both nutritional and environmental properties

Health Check

First sensor verifies if the product is low in fat (low_fats = 'Y')

Environmental Check

Second sensor verifies if the packaging is recyclable (recyclable = 'Y')

Decision Gate

Only products passing BOTH checks are directed to the 'Healthy & Green' collection bin

Key Takeaway

🎯 Key Insight: The AND operator in SQL acts like a quality gate that requires ALL conditions to be true simultaneously, making it perfect for multi-criteria filtering scenarios like this health and environmental compliance check.

Asked in

a Amazon 25 ⊞ Microsoft 18 G Google 15 f Meta 12

This problem is solved with a simple SQL SELECT statement using a WHERE clause with AND condition. The key insight is to filter rows where both low_fats = 'Y' AND recyclable = 'Y' simultaneously. This approach has O(n) time complexity and is the most straightforward solution for this filtering requirement.

Common Approaches

Approach	Time	Space	Notes
✓ Basic SQL Query with AND Condition	O(n)	O(1)	Simple SELECT query with WHERE clause checking both conditions

Basic SQL Query with AND Condition — Algorithm Steps

Scan through all rows in the Products table
For each row, check if low_fats = 'Y'
For the same row, check if recyclable = 'Y'
If both conditions are true, include the product_id in results
Return all qualifying product IDs

Visualization

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Step-by-Step Walkthrough

Start Scan

Begin scanning from the first row of the Products table

Check Conditions

For each row, evaluate both low_fats = 'Y' AND recyclable = 'Y'

Filter Results

Include product_id in result set only if both conditions are true

Continue Scan

Move to next row and repeat until all rows are processed

Code -

solution.c — C

Time & Space Complexity

Time Complexity

⏱️

O(n)

Linear scan through all n rows in the Products table

✓ Linear Growth

Space Complexity

O(1)

Only stores the result set, no additional data structures needed

✓ Linear Space

78.5K Views

High Frequency

~5 min Avg. Time

3.3K Likes

Ln 1, Col 1

Smart Actions

💡 Explanation

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🌱 Recyclable and Low Fat Products

Input & Output

Constraints

Visualization

Related Problems

Common Approaches

Basic SQL Query with AND Condition — Algorithm Steps

Visualization

Code -

Time & Space Complexity

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