Technical Interviews: A Practical Guide from Preparation to Offer

The Honest Truth About Technical Interviews

Technical interviews are not a perfect measure of engineering skill — but they're the gate you have to pass. So let's pass them efficiently.

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Phase 1: Data Structures & Algorithms

You don't need to memorise 500 LeetCode problems. You need to recognise 15 patterns.

The Core Patterns

Pattern	When to use	Key data structure
Sliding Window	Contiguous subarray/substring	Array, String
Two Pointers	Sorted arrays, pairs	Array
Fast & Slow Pointers	Cycles, middle of list	Linked List
Merge Intervals	Overlapping ranges	Array
Cyclic Sort	Sorted range, missing numbers	Array
Binary Search	Sorted input	Array
BFS	Shortest path, level order	Queue
DFS	Tree traversal, paths	Stack/Recursion
Dynamic Programming	Optimal substructure	Array/Map
Backtracking	Combinations, permutations	Array

Sliding Window Example

def max_sum_subarray(arr, k):
    window_sum = sum(arr[:k])
    max_sum = window_sum
    for i in range(k, len(arr)):
        window_sum += arr[i] - arr[i - k]
        max_sum = max(max_sum, window_sum)
    return max_sum

Study Order (4-6 weeks)

Week 1: Arrays, Strings, Hash Maps
Week 2: Linked Lists, Stacks, Queues
Week 3: Trees, BFS, DFS
Week 4: Graphs, Union Find
Week 5: Dynamic Programming (start easy)
Week 6: Mock interviews on Pramp or interviewing.io

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Phase 2: System Design

For mid-level and senior roles, system design is often more important than DSA.

Framework: RESHADED

• R — Requirements (clarify functional & non-functional)
• E — Estimation (users, QPS, storage)
• S — Storage (SQL vs NoSQL, schema)
• H — High-level design (boxes and arrows)
• A — APIs (REST endpoints)
• D — Deep dive (bottlenecks, scale)
• E — Edge cases
• D — Discuss trade-offs

Key Concepts to Know

• Load balancing: Round-robin, least connections, consistent hashing
• Caching: Redis, CDN, cache invalidation strategies
• Databases: SQL vs NoSQL, sharding, replication, indexing
• Message queues: Kafka, RabbitMQ for async processing
• CAP theorem: Consistency, Availability, Partition tolerance

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Phase 3: Behavioural Questions — STAR Method

Situation → Task → Action → Result

Prepare 5-6 stories that can answer most behavioural questions:

1. Biggest technical challenge you overcame
2. Conflict with a teammate — how you resolved it
3. Project you're most proud of
4. Time you failed and what you learned
5. Tight deadline — how you prioritised

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Phase 4: The Interview Day

• Think out loud — interviewers want to see your process
• Clarify before coding — ask about edge cases, constraints
• Write a brute force first, then optimise
• Test with examples before saying you're done
• Ask good questions at the end:
  • "What does the first 90 days look like?"
  • "What's the biggest technical challenge the team faces?"
  • "How is success measured for this role?"

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Phase 5: Negotiation

Always negotiate. The first offer is rarely the best offer.

• Get the offer in writing before negotiating
• Research salaries on Glassdoor, Levels.fyi, LinkedIn Salary
• Negotiate base, equity, signing bonus as a package
• Use the silent pause: state your counter and wait

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Questions? Connect on LinkedIn — happy to do mock interviews too.