DSA & beyond - Mastery Roadmap : How to Learn

🧠 DSA & more - Mastery Roadmap

1. 🧪 Understand the Problem

• Start by writing 3 to 5 small test cases
• Use RunCode (not Submit) to verify the expected outputs
• Confirm input format, constraints, edge cases
• Understand problem deeply before thinking of code

• Read the problem statement twice to catch subtle requirements +*
• Identify edge cases: empty inputs, single elements, maximum/minimum constraints +*

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2. 🧠 Plan Before Coding

• Identify problem category: Tree / Graph / Greedy / Bit Manipulation / DP
• Think of multiple approaches and weigh trade-offs
• Consider if the problem combines topics (e.g., Bit + String)

• Choose optimal data structures early (HashMap vs Array, Stack vs Queue) +*

• Estimate time and space complexity -

• Write down your approach in 2-3 bullet points before coding +*

• Set a 30-minute timebox to simulate interview constraints -

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3. 💻 Code & Validate

• Write clean, readable code (even if initial)
• Run small test cases using RunCode

• Dry-run your algorithm on paper for complex problems +*
• Test edge cases explicitly (empty, single element, max constraints) +*

• Run on max input case (e.g., array with 40K elements)
• Monitor RunCode time (e.g., 200ms = slow)
• If TLE or high runtime → do not submit yet

• When solution fails, systematically trace through failing test cases +*

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4. 🔁 Revisit Later (if incomplete)

• Leave the problem — let it sit for a few days
• Trust that RunCode has saved your progress
• Revisit after 1–3 weeks with more understanding
• Attempt again with a better, optimized approach
• Submit only when runtime and memory are acceptable

• Implement spaced repetition: revisit solved problems after 1 week, 1 month, 3 months +*

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5. 📚 Learn from Community

• Read the official solution
• Visit Discuss tab → Filter by Most Votes and your language (e.g., Java)
• Read top 5–10 posts and understand their insights -

• Focus on solutions that are both efficient AND readable, not just fastest +*

• Open the Runtime Graph of submissions:

  • Click left-most bar = fastest solutions
  • Study their code and compare to yours

• Save interesting patterns, one-liners, or tricks in a personal log -

• Document key insights and patterns in your learning log +*

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6. 🧩 Build Patterns & Efficiency

• Maintain a notebook or log of ideas/mistakes -

• Keep a pattern library organized by problem type (Two Pointers, Sliding Window, etc.) +*

• Reapply patterns you learned in future problems
• Try to write faster and shorter code each time
• Review older submissions to observe your improvement
• Keep repeating this cycle until intuition builds

• Track your success rate and average time-to-solve by topic +*
• Hold weekly review sessions to consolidate learned patterns +*

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7. 📈 Smart Practice Strategy

• Focus first on:

  • Easy + Array
  • Easy + String
  • Easy + Math

• Follow progression: Easy → Medium → Hard within each topic before switching +*

• Filter problems by topic + high acceptance rate

• Choose problems with 999+ Discuss posts

  • These are well-tried and often better explained

• Avoid new problems with misleading high acceptance (may be tricky or buggy) -

• Start each practice session by reviewing 1–2 previously solved problems +*

• Always study runtime/memory graphs and try to learn from the top submissions

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8. 🧠 When Problems Get Too Hard

• There will be a point where solving becomes hard — everyone hits a limit

  • For some it’s at 100, for others 500 or 2000+
  • At this stage, the goal is to learn by reading solutions
  • Understand the solution deeply, then implement it from scratch without looking
  • That way, you retain the learning and build intuition

• Don’t try to rediscover advanced topics like DP from scratch

  • Instead, save time by studying existing patterns and applying them

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9. 🧠 Interview Prep Add-ons

• Join peer-to-peer code reviews weekly -

• Practice explaining your solution out loud while coding +*

• Schedule mock interviews (Pramp, Interviewing.io, etc.)

• Do weekly timed problem-solving sessions (3-4 problems in 90 minutes) +*

• Study system design basics (for later stages) -

• Practice whiteboard coding without IDE assistance +*

• Prepare 1–2 behavioral stories each week (STAR format) -

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🎯 Outcome

• Faster problem-solving with confidence
• Sharper understanding of patterns and optimization
• Better preparation for real interviews

• Consistent performance under time pressure +*
• Strong pattern recognition across problem types +*

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🔹 Original Messages from Coach (2222+ solved ), in Sequence:

1. first, i write small number of test cases - normal cases - like 5 elements in an array

2. verify if my understand is correct by RunCode (not submit) with the test cases i have

3. now i know, the input & expected output correctly - that means - i understood the problem

4. i think of solution - how to code - by what approach

   • is it tree - then is it dfs, bfs, etc.
   • is it graph - then any algo i shud use?
   • is it greedy ?
   • is it bit manipulation
   • is it DP
   • etc,

5. then i think if i have to apply multiple topics (for example, bit manipulation + strings)

6. now i know if that will Pass the RunCode or not

7. code is run using RunCode

   • i see the time 80 ms, etc is ok
   • but if it is 200 ms then there might be a problem (for large test cases)

8. now i create large test case

   • for example, array max length is given as 40,000 elements
   • then i create that test case and try run code

9. now i will knw if that is TimeLimitExceed etc.

10. if i see it is TLE in RunCode

    • i will not submit (wont make sense)
    • i leave the problem here
    • coz i know i solved it, need to improve it

11. i wont remember it

    • but RunCode remembers code

12. may be after some days, may be 20 days

    • i will be more knowledgeable then i will retry (i wont care what i wrote earlier)
    • if my ms is better - then i will submit the code
    • this time most probably it will Pass

13. assume if i solved problem

    • then i look at solution
    • for example - this link for ur case

14. now i read solutions from discuss

    • i search for my programming lang (like ur case is Java)

    • that link is saying

    • give me "Most votes" & "Java" solutions only

    • click on "Most votes" then type "java" in search bar

    • that all

    • then i read ALL posts

    • from the above link

    • i will understand at least half of it

      • since it is my programming language 14.a - i will learn to write short code 14.b - i will learn other ideas that i dont know

15. now i have short-codes + more ideas for next problem

    • so most probably
    • i will write quicker code
    • and i will get better solution
    • the success rate will increase drastically

16. again i read ALL submissions

17. now i am have several ideas

    • and i know which are better than mine, etc.

18. now it comes to

    • first i shud solve
    • then i can get more help

19. so, i solve

    • only Easy ones
    • only Arrays
    • this kind of Topic-wise solving is extremely useful

20. so i solve as below:

    • Easy + Array
    • Easy + Strings
    • Easy + Math
    • may be i will leave some

21. first i click on Acceptance Rate

    • that gives me those that r solved by others
    • sorting by Acceptance rate is important

22. For example

    • i have many acceptance rate between 85 & 90

    • then which is better to solve?

    • i open all problems between them

    • then see how many discussion posts are there

    • if posts of the question 999+

      • it is good to solve

    • some questions are new

      • only few will try
      • then those ppl who solved might take the acceptance rates high
      • but they r not easy

    • also the problem might be very new

    • in these cases

      • the discuss posts will be like 200, 300, .. 700 etc,

23. so enough knowledge for today ?

24. i talk to many ppl

    • so i can only spend so much time

25. perfect

    • apply them
    • and sync back after 2 days
    • every alternate day u can sync
    • if u have less to talk - u can sync every day (after a week or so)

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two important points ( learning achieved after 2000+ problems solved )

26. when problems become too hard

    • then we have to see solutions and learn, understand, and then code without seeing
    • thats what i am at now at 2222, i cannot solve anymore
    • we might hit this limit at any time, for me at 2000, for someone else it might be 500, or 100

27. instead of trying for 3 days a problem - and rediscovering DP ( i did ) we can learn existing patterns - we can save time by learning existing patterns like DP

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