Tech Interview Preparation: Algorithms, System Design, and Behavioral Questions

## The Tech Interview Process Tech company interviews typically consist of 4-6 stages: 1. **Phone Screening** (30-45 min) 2. **Technical Phone Interview** (45-60 min) 3. **Coding Challenge** (Take-home or live) 4. **Onsite/Virtual Interview** (3-5 hours, 4-6 rounds) 5. **Hiring Manager Discussion** 6. **Culture Fit/Behavioral** ## Data Structures & Algorithms ### Core Topics **Data Structures**: - Arrays and Strings - Linked Lists - Stacks and Queues - Hash Tables - Trees (Binary, BST, AVL) - Heaps - Graphs - Tries **Algorithms**: - Searching (Binary Search, DFS, BFS) - Sorting (Quick, Merge, Heap Sort) - Dynamic Programming - Greedy Algorithms - Backtracking - Divide and Conquer ### Study Plan (8 Weeks) **Weeks 1-2**: Array/String (15 problems), Linked List (10), Stack/Queue (10) **Weeks 3-4**: Trees (15 problems), BST (10), Graph (15) **Weeks 5-6**: Dynamic Programming - 1D (10), 2D (10), Advanced (5) **Week 7**: Greedy (10), Backtracking (10) **Week 8**: Mock interviews and review ### Best Resources - **LeetCode**: Blind 75 question list - **HackerRank**: Interview preparation kit - **AlgoExpert**: Comprehensive solutions - **Books**: "Cracking the Coding Interview" by Gayle McDowell ## Problem-Solving Framework **UMPIRE Method**: 1. **Understand**: Clarify inputs, outputs, edge cases 2. **Match**: Identify patterns and data structures 3. **Plan**: Write pseudocode, calculate complexity 4. **Implement**: Write clean, readable code 5. **Review**: Test edge cases, check syntax 6. **Evaluate**: Analyze time/space complexity, optimize ## System Design Interview ### Common Questions - Design URL Shortener (TinyURL) - Design Twitter/X - Design YouTube - Design WhatsApp - Design Uber/Lyft - Design Rate Limiter ### Approach 1. **Requirements** (5 min): Functional vs non-functional, scale, users 2. **Estimation** (5 min): QPS, storage, bandwidth, cache 3. **High-Level Design** (10-15 min): API, database, components 4. **Deep Dive** (15-20 min): Scaling, bottlenecks, caching, load balancing 5. **Wrap-Up** (5 min): Trade-offs, monitoring, deployment ### Key Concepts - **Scalability**: Horizontal/vertical scaling, load balancing, caching, CDN, sharding - **Reliability**: Replication, failover, backups - **Performance**: Indexing, caching, async processing, message queues **Resources**: Grokking System Design, System Design Primer (GitHub), "Designing Data-Intensive Applications" ## Behavioral Interview ### STAR Method **S**ituation: Set the context **T**ask: Describe your responsibility **A**ction: Explain what you did **R**esult: Share the outcome ### Common Questions 1. Tell me about yourself 2. Why this company? 3. Biggest strength/weakness 4. Conflict resolution example 5. Leadership experience 6. Failure and learning 7. Challenging project 8. Tight deadline experience 9. Disagreement with manager 10. Questions for interviewer ### Preparation Tips - Research company culture thoroughly - Use their products - Read tech blog - Follow recent news - Prepare questions to ask ## Mock Interviews **Platforms**: - **Pramp**: Free peer interviews - **interviewing.io**: Anonymous practice - **Gainlo**: Experienced interviewers - **Exponent**: System design focused ## Interview Day Tips **Before**: - Sleep well - Test equipment - Review notes - Do final company research **During**: - Think out loud - Ask clarifying questions - Discuss trade-offs - Accept hints gracefully **After**: - Send thank-you email (within 24 hours) - Take notes on what went well/poorly - Follow up on timeline ## Prepare with Rejectly Rejectly helps with: - Company-specific CV optimization - Skill highlighting for positions - STAR method story creation - Mock interview question prep [Start interview preparation](/dashboard) ## Final Thoughts Tech interview prep is a marathon, not a sprint. Consistent practice, mock interviews, and learning from failures are key to success. **Average Prep Time**: - Entry-level: 2-3 months - Mid-level: 1-2 months - Senior: 3-4 weeks Remember: Every interview is a learning opportunity!