Tips for Mastering Algorithms

I spent 2+ years grinding Leetcode and learning DSA & problem-solving as a CSE student at BITS Pilani. If I had to start again from 0, this is exactly how I’d do it to get hired as a Software Engineer in 2025:  1️⃣ 𝗺𝗮𝘀𝘁𝗲𝗿 𝗰𝗼𝗿𝗲 𝗮𝗹𝗴𝗼𝗿𝗶𝘁𝗵𝗺𝘀 𝗯𝗲𝗳𝗼𝗿𝗲 𝗮𝗻𝘆𝘁𝗵𝗶𝗻𝗴 𝗲𝗹𝘀𝗲 ○ Before touching random Leetcode problems, I’d master core algorithms like: Binary Search, DFS, BFS, Sliding Window, Two Pointers, Recursion, Backtracking, and Dynamic Programming. ○ The goal isn’t just to “understand” these but to be able to implement them from scratch without hesitation. ○ I’d write each algorithm at least 5-10 times from memory until it becomes second nature.  2️⃣ 𝗳𝗼𝗰𝘂𝘀 𝗼𝗻 𝗽𝗿𝗼𝗯𝗹𝗲𝗺 𝗽𝗮𝘁𝘁𝗲𝗿𝗻𝘀, 𝗻𝗼𝘁 𝗷𝘂𝘀𝘁 𝘀𝗼𝗹𝘃𝗶𝗻𝗴 𝗽𝗿𝗼𝗯𝗹𝗲𝗺𝘀 ○The biggest mistake people make is solving hundreds of random problems without recognizing patterns. ○ 90% of interview problems fall into ~20 coding patterns. ○ Instead of solving 1000+ questions, I’d focus on understanding:    ►How problems within a pattern are similar.    ►What small variations make them different.    ►Which techniques help optimize them.  3️⃣ 𝗿𝗲𝗽𝗲𝗮𝘁 𝗽𝗿𝗼𝗯𝗹𝗲𝗺𝘀 𝗶𝗻𝘀𝘁𝗲𝗮𝗱 𝗼𝗳 𝗷𝘂𝘀𝘁 𝗺𝗼𝘃𝗶𝗻𝗴 𝗼𝗻 ○ Just because I solved a problem once doesn’t mean I’ll remember it. ○ I’d follow this reinforcement schedule for problems I struggled with: Solve it today, solve it again in 1 week and finally solve it again in 1 month. ○This is how I’d make sure I actually retain what I learn.  4️⃣ 𝘀𝘁𝘂𝗱𝘆 𝘀𝗼𝗹𝘂𝘁𝗶𝗼𝗻𝘀 𝘁𝗵𝗲 𝗿𝗶𝗴𝗵𝘁 𝘄𝗮𝘆 ○ When I can’t solve a problem, I’d first struggle with it for at least 30 minutes before looking at the solution. ○ Then, I’d:   ► Write out the solution from memory after understanding. ► Explain why it works in simple words ► (if I can’t explain it, I don’t truly understand it).   ► Look at alternative solutions to compare trade-offs.  5️⃣ 𝗯𝘂𝗶𝗹𝗱 𝗮 𝘀𝘁𝗿𝘂𝗰𝘁𝘂𝗿𝗲𝗱 𝗽𝗿𝗼𝗯𝗹𝗲𝗺 𝗹𝗶𝘀𝘁 (𝗻𝗼𝘁 𝗷𝘂𝘀𝘁 𝗿𝗮𝗻𝗱𝗼𝗺 𝗴𝗿𝗶𝗻𝗱𝗶𝗻𝗴) ○ Instead of jumping between random problems, I’d follow a structured roadmap like:  ► First 50-60 easy problems → Get comfortable with implementation.   ► Next 80-100 medium problems → Focus on pattern recognition & optimization.   ► Last 30-40 hard problems → Only after mastering the fundamentals.  ○ 150-200 well-selected problems are enough to crack most interviews.  6️⃣ 𝘀𝘁𝗮𝗿𝘁 𝗺𝗼𝗰𝗸 𝗶𝗻𝘁𝗲𝗿𝘃𝗶𝗲𝘄𝘀 𝗲𝗮𝗿𝗹𝘆 (𝗲𝘃𝗲𝗻 𝘄𝗵𝗲𝗻 𝗜 𝗳𝗲𝗹𝘁 𝘂𝗻𝗽𝗿𝗲𝗽𝗮𝗿𝗲𝗱)   ○ Simulating real interviews early helps with time pressure & communication skills.  ○ I’d start setting strict 30-45 min timers on problems to simulate interview conditions.  ○ I’d practice explaining my thought process out loud, since half of the interview is about communication.  (Bonus tip in the comments) ↓

🎯 400 LeetCode problems solved - but this isn't your typical "grinding problems" post. Like training a machine learning model, I approached algorithmic problem-solving with a focus on data quality and diversity. Just as ML models need varied, high-quality data points to generalize well, I found that solving diverse problems across different patterns and domains builds better problem-solving intuition. My systematic approach: Pre-coding Analysis (Link to sample doc in comments) • Document multiple potential approaches • Analyze time & space complexity for each approach • Think through tradeoffs before writing any code • Consider edge cases and constraints Practice Execution • Used stopwatch to measure performance • Aimed to solve while explaining clearly within: - Easy: 10 minutes - Medium: 15 minutes - Hard: 25 minutes • Focus on thinking aloud - crucial for interviews Deep Dive Process • Rigorous complexity analysis • Explore optimization opportunities • Document learnings and patterns • Regular mock interviews on Pramp The goal wasn't to solve all 3000+ problems, but to build a robust "model" that could generalize to new problems effectively. Each solved problem is like a new training data point, helping my brain recognize patterns and edge cases. Key learning: The magic happens in the pre-coding analysis. Writing down different approaches and analyzing tradeoffs before coding helped me: - Build stronger problem-solving intuition - Communicate my thought process clearly - Make better engineering decisions - Save time during actual coding I'll share a sample doc in the comments. It's been crucial for building a systematic approach to problem-solving. To those on this journey: Keep your head down, document your thinking, and remember - you're not just solving problems, you're building a framework for approaching any technical challenge.

17 LeetCode free Tips that people will charge you money for (after cracking 10+ Interviews & solving 1000+ pblms) If you’re starting LeetCode, I am supposing you already know a coding language and you have a good hold of basics and its libraries. Don’t even dare to search Leetcode on your browser before it, just joking :D Here are the tips: 1. Start Easy: Begin with easy problems to refresh your coding muscles and build confidence. 2. Go Wide, Not Deep (Initially): Do 5–6 easy problems per topic to grasp core concepts before moving on. 3. Master the Basics: Use easy problems to nail down language syntax, DS fundamentals, and common patterns. 4. Look for Combinations: Tackle problems that mix 2–3 data structures—they teach how tools work together. 5. Graduate Quickly: Move to medium problems once you're comfortable. Interviews rarely ask easy ones. 6. Breadth First, Again: For mediums, solve 8–10 problems per topic. Focus on learning techniques, not quantity. 7. Embrace the Struggle: It's okay to use hints or discussions—just ensure you understand the approach. 8. Don't Memorize Solutions: Focus on why a solution works. Interviews test problem-solving, not recall. Don’t use YT videos for finding solutions, use the Discuss Section. 9. Theory Matters: Read up on core topics (e.g., trees, graphs, DP, backtracking) while solving related problems. 10. Start Contests Early: After ~60–70 mediums, start participating in contests. They simulate real interviews. 11. Learn from Others: Study optimized solutions, compare trade-offs, and ask for help when stuck. 12. Build a Pattern Bank: Track the common patterns (sliding window, two pointers, BFS/DFS, etc.) and revisit them. 13. Stay Consistent: Even 1–2 problems a day adds up. It’s a marathon, not a sprint. 14. Document your journey - Preserve problems solved with hints, solve them later and leave some personal tips for each topic for quick revision in future. 15. Review Regularly: Revisit problems you couldn’t solve. Understanding them later is a real confidence boost. 16. Have a coding buddy: I seriously can’t imagine my coding journey without @Rohit. Good friends who are focused as you make your journey easy. 17. Last tip but most important - Most people never ace Leetcode because they never give it a good shot. Give yourself 8 weeks to learn, fail and feel like stupid. If you can suppress that feeling of doubt for 8 weeks, you will ace Leetcode for sure. P.S.: The next 6 posts will be all about Leetcode too. I will be sharing 6 years worth prep and 2 years worth teaching secrets to you in these posts. Follow and don’t forget to press the bell Suresh G.