Why one course, and how many hours it implies
Switching between several question banks feels productive but makes it hard to tell what you have covered. Anchoring to one structured source gives you a checklist. Educative's Grokking the Coding Interview Patterns page lists 28 coding patterns, 1,125 lessons, 579 quizzes, 500+ challenges, 17 AI mock interviews and about 85 hours, in C#, C++, Go, Java, JavaScript and Python [1]. Its system design course lists about 26 more hours [2].
Worked maths: 85 plus 26 hours is 111 listed hours. Over 12 weeks that is about 9.25 hours a week before any mock interviews or review. Most people with a job cannot do all of it, so the plan below covers the patterns and uses the rest selectively. If your budget is zero, the free Tech Interview Handbook offers curated preparation material, including its Grind 75 question list, under an MIT license [4].
The 12-week calendar
The review column is the point of the plan. Dunlosky and colleagues rated distributed practice and practice testing as high utility study techniques [3]. Re-solving an old problem from a blank editor is both.
| Weeks | Focus | Hours per week | Review rule |
|---|---|---|---|
| 1 to 2 | Arrays, strings, hash maps, linked lists, stacks, queues, trees, graphs; language syntax refresh | 8 to 10 | End of week 2: redo 5 earlier problems without notes |
| 3 to 4 | First patterns: two pointers, sliding window, fast and slow pointers, merge intervals | 10 | Each week: 3 problems from patterns learned 1 to 2 weeks ago |
| 5 to 6 | Tree and graph traversal patterns, heaps, binary search variants | 10 | Mixed set of 6 problems from all earlier patterns |
| 7 to 8 | Backtracking, dynamic programming basics; start system design building blocks | 12 | Mixed set plus one design topic recap |
| 9 to 10 | System design case studies; remaining patterns you have skipped | 12 | One timed 45-minute coding problem every other day |
| 11 to 12 | Mock interviews (coding and design), weak-area repair | 10 to 12 | Redo every problem you failed in weeks 3 to 10 |
Where a paid course and free material slot in
Timing a paid plan matters. Educative's trial page says interview prep courses are excluded from its 21-day free trial [5], so do not plan to finish the patterns course on a trial. Weeks 1 to 2 can use free material while you decide.
| Part of the plan | Paid option | Free option |
|---|---|---|
| Pattern lessons and problems | Grokking the Coding Interview Patterns: 28 patterns, 500+ challenges [1] | Tech Interview Handbook and its Grind 75 list [4] |
| System design | Grokking Modern System Design Interview: about 26 hours, 77 free lessons [2] | Free preview lessons, then free primers and books (see our system design course guide) |
| Mock interviews | AI mock interviews listed on both course pages [1] [2] | A friend or colleague with a timer and a rubric you write |
| Review | Course quizzes [1] | Your own list of failed problems, redone on a schedule |
A sample week (week 5, about 10 hours)
- Monday, 90 minutes: two new tree traversal lessons and their challenges.
- Tuesday, 90 minutes: three problems on the new pattern without hints.
- Wednesday, 60 minutes: review set of three problems from weeks 3 and 4.
- Thursday, 90 minutes: heap lessons and two challenges.
- Friday, 60 minutes: redo Tuesday's hardest problem from scratch.
- Saturday, 2 hours: mixed set of six problems across all patterns so far, timed.
- Sunday, 30 minutes: update the failed-problem list and plan next week.
Adjusting the plan
With only 6 hours a week, stretch the same sequence to about 18 weeks rather than cutting the review sessions. With an interview in 6 weeks, compress weeks 1 to 2 into a few days if your data structures are solid, keep the review rule, and start mock interviews by week 4.
Skip lessons on patterns you already solve reliably on the first try. The goal is not course completion; it is being able to identify the pattern in an unfamiliar problem and implement it under time.
Checklist before week 1
This is an editorial plan built from published course lengths and study research. We have not followed it ourselves or measured interview outcomes.
- Pick one language and stay with it; the patterns course supports six [1].
- Decide your anchor source: paid course or free list [1] [4].
- Block study time on a calendar for all 12 weeks, including review sessions.
- Create a failed-problem list with the date and the reason you failed.
- Check whether your target course is in any trial before relying on one [5].
Questions before you decide
How many hours a week does a 12-week coding interview plan need?
The two Educative courses discussed here list about 85 and 26 hours, which is roughly 9 hours a week over 12 weeks before mock interviews and review. Around 10 to 12 hours a week is a realistic target.
Can I do this plan on the Educative free trial?
Not the interview prep parts. Educative's trial page says interview prep courses are excluded from the free trial offer.
Is there a free alternative to a paid patterns course?
Yes. The Tech Interview Handbook offers free curated preparation material, including the Grind 75 question list, under an MIT license.
Sources & verification
Product details and prices can change. Check the linked provider before buying.
- Educative: Grokking the Coding Interview Patterns course page Accessed 30 Oct 2026
- Educative: Grokking Modern System Design Interview course page Accessed 30 Oct 2026
- Duke Scholars: Dunlosky et al. (2013), Improving students' learning with effective learning techniques (abstract) Accessed 30 Oct 2026
- GitHub: Tech Interview Handbook (yangshun/tech-interview-handbook) Accessed 30 Oct 2026
- Educative: 21-day free trial page Accessed 30 Oct 2026
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