Prepare for coding interviews by reviewing core data structures and algorithms, practising problems grouped by pattern, solving them while explaining your thinking aloud, timing yourself, preparing to discuss your projects in depth, and rehearsing behavioural questions. Eight weeks of consistent daily practice is a realistic plan for most junior roles.
What coding interviews test
- Problem solving: can you break down an unfamiliar problem?
- Coding: can you write correct, readable code?
- Communication: can you explain your reasoning and respond to hints?
- Fundamentals: do you understand data structures and complexity?
- Experience: can you discuss real projects and decisions?
- Fit: how do you work with others and handle challenges?
The 8-week plan
| Week | Focus |
|---|---|
| 1 | Arrays, strings, hash maps; Big O notation |
| 2 | Two pointers, sliding window |
| 3 | Stacks, queues, linked lists |
| 4 | Recursion, sorting, binary search |
| 5 | Trees and tree traversal |
| 6 | Graphs: BFS and DFS |
| 7 | Dynamic programming basics; mixed practice |
| 8 | Mock interviews, projects and behavioural questions |
Spend about 60 to 90 minutes a day, solving one or two problems properly rather than skimming many.
How to practise properly
- Read and clarify. Restate the problem and ask about edge cases.
- Think aloud. Describe a simple approach first, then improve it.
- Write clean code. Clear names and structure.
- Test by hand with normal and edge-case inputs.
- Analyse complexity: time and space.
- Review afterwards. If you were stuck, study the solution, then solve it again from scratch two days later.
Learn patterns, not answers
Most problems are variations of a few dozen patterns. Recognising "this is a sliding window problem" is more valuable than memorising solutions. See data structures explained simply.
Your projects matter
Prepare to explain two projects in depth: the problem, architecture, your role, challenges, trade-offs and what you would improve. Many junior interviews focus here as much as on puzzles.
Behavioural questions
Prepare short stories using the STAR method (situation, task, action, result) for teamwork, conflict, failure, learning something quickly and meeting a deadline. See how to prepare for a job interview.
Mock interviews
Practise with a friend, mentor or tutor. Speaking while solving feels very different from solving silently. Our tutors run mock technical interviews for university students and career changers.
Frequently asked questions
Which language should I use in interviews?
The one you know best, as long as the company allows it. Python is popular because it is concise.
How many problems should I solve?
Quality beats quantity. A hundred well-understood problems across patterns is better than 400 skimmed.
What if I get stuck in the interview?
Say what you are thinking, try a simpler version of the problem, and use hints. Interviewers value calm problem-solving.
