# Foundations Index

If you’re targeting multiple company archetypes, foundations are your unfair advantage: they transfer between domains and reduce interview variance.

This folder is split into foundations that show up in _most_ loops:

- Coding fundamentals (data structures, algorithms, complexity)
- Computer systems (OS, networking)
- Databases (modeling, indexing, transactions)
- Engineering craft (testing, debugging, maintainability)
- Cloud + reliability basics

## How to study foundations efficiently

### The “practice loop”

For each topic, do a weekly loop:

1. Read 1–2 short references
2. Implement 1–3 small exercises
3. Do 1 timed interview-style prompt
4. Write a post-mortem: what failed, why, what rule prevents it next time

### What _not_ to do

- Don’t binge-watch content without doing reps.
- Don’t memorize solutions; memorize _problem types_ and _decision rules_.

## Company archetype weighting (rough)

- **FAANG/high-growth:** strongest weight on coding + system design communication.
- **Enterprise:** weight shifts toward maintainability, migrations, and operating in constraints.
- **Automotive/industrial:** higher emphasis on correctness, traceability, and risk management.

## Recommended order (4 weeks)

Week 1

- Coding mechanics + complexity
- OS basics (process vs thread, memory)

Week 2

- Networking (HTTP, TCP, latency)
- Databases (indexes, transactions)

Week 3

- Reliability basics (SLOs, retries, timeouts)
- Debugging + testing practices

Week 4

- Cloud primitives (compute, storage, queues)
- Combine topics in system design exercises

## Next pages

- [01-DSA-and-Coding.md](01-DSA-and-Coding.md)
- [02-Computer-Systems.md](02-Computer-Systems.md)
- **[03-DSA-Topic-Breakdown.md](03-DSA-Topic-Breakdown.md) — NEW:** Patterns & intuition for arrays, trees, DP, heaps, hashing, bits
- [04-Databases.md](04-Databases.md)
- [05-Software-Engineering-Practices.md](05-Software-Engineering-Practices.md)
- [06-Cloud-and-Reliability-Basics.md](06-Cloud-and-Reliability-Basics.md)