Databricks

Design a MockHashMap class that tracks operation frequency.

Required Methods:

1. Basic HashMap Operations:

put(key, val)  // Insert key-value pair
get(key)       // Retrieve value for key

2. Load Measurement Methods:

measure_put_load()  // Average put calls/second in last 5 minutes
measure_get_load()  // Average get calls/second in last 5 minutes

Implementation Requirements:

• Record timestamp for each operation
• Calculate 5-minute rolling averages
• Filter records within time window
• Divide by 300 seconds for average

Example:

// 600 put calls in 5 minutes
measure_put_load() → 2.0  // (600/300 seconds)

// 150 get calls in 5 minutes
measure_get_load() → 0.5  // (150/300 seconds)

Design a web crawler that downloads pages up to depth K from a start URL.

Core Requirements:

1. Crawling Logic:

• Start from start_url
• Crawl recursively up to depth K
• Extract and follow links

2. Storage Management:

• Create directory structure for downloads
• Store pages based on URL and depth
• Efficient storage organization

3. Robustness:

• Track visited URLs (deduplication)
• Detect and handle cycles
• Handle malformed URLs

Follow-up Questions:

1. Distributed Architecture:

• How to parallelize crawling?
• Handle shared state
• Load balancing

2. Performance:

• Handle slow responses
• Implement timeouts
• Rate limiting