DEV Community: Vrinda Khandelwal

🚀 Day 5 of LeetCode Grind

Vrinda Khandelwal — Thu, 28 Aug 2025 17:50:38 +0000

oday was all about Linked Lists 🧵.

✅ Solved:

Reverse Linked List (Easy, confidence booster 💪)
Merge Two Sorted Lists (Easy, smooth ride ✨)
Linked List Cycle (Easy, but took some thinking 🔄)
Remove Nth Node From End of List (Medium — pointers game, tricky at first 👀)
Add Two Numbers (Medium — felt like a mini project itself, lots of debugging 😅)

🔑 Takeaway:

Easy ones built momentum.

Medium ones tested patience but also gave that “aha!” moment.

Linked lists are slowly starting to feel less scary, more like puzzles 🧩.

Tomorrow: continuing the grind → maybe tackling some stack/queue problems.

🚀 Day 4 – Strings Advanced (LeetCode Challenge)

Vrinda Khandelwal — Tue, 26 Aug 2025 18:54:34 +0000

Today was all about strings – not the musical ones 🎸 but the tricky coding ones.
I jumped into some advanced string problems, and wow, they really stretched my brain.

Problems I tackled:

🔎 [76] Minimum Window Substring – Sliding window at its finest. Took a while to wrap my head around all the shrinking and expanding, but it’s honestly such a beautiful pattern.

✅ [20] Valid Parentheses – Classic stack problem. Still satisfying every single time the brackets line up just right.

➕ [415] Add Strings – No built-in big integer magic here, just pure digit-by-digit addition like we did in school.

🔄 [151] Reverse Words in a String – Reminded me that trimming spaces and reversing aren’t as simple as they sound.

🌱 [14] Longest Common Prefix – Surprisingly elegant once you see the trick of comparing characters across strings.

💡 Takeaways:

Sliding window problems demand patience (and lots of debugging 😅).

Stacks are lifesavers when things need to stay in order.

Sometimes coding feels like going back to primary school math (and that’s not a bad thing).

"Simple" string problems can hide messy details – trimming spaces, handling edge cases, etc.

✨ That’s a wrap for Day 4. Strings may look simple, but they sure know how to test logic and patience. On to Day 5 tomorrow!

🌟 Day 3 of My 150 Days of DSA Journey – Strings Special

Vrinda Khandelwal — Mon, 25 Aug 2025 18:19:45 +0000

Hello everyone! 👋
Today marks Day 3 of my 150 Days of DSA Challenge. I decided to dive into string problems, and honestly, they were tricky but super interesting! Strings always look simple but can test your patience with edge cases.

Here are the problems I worked on today:

🔹 [3] Longest Substring Without Repeating Characters

Idea: Use a sliding window + last seen index of characters.

Learning: Hashing/index tricks help reduce time from O(N²) → O(N).

🔹 [5] Longest Palindromic Substring

Idea: Expand around center (each char / pair as a middle).

Learning: Elegant O(N²) solution; DP works too, but expand-around-center feels intuitive.

🔹 [125] Valid Palindrome

Idea: Use two pointers from both ends, ignore non-alphanumeric chars.

Learning: Careful with character checks, but it’s straightforward.

🔹 [49] Group Anagrams

Idea: Sort each string → use as a key → group together.

Learning: Sorting + hashing go hand in hand!

🔹 [242] Valid Anagram

Idea: Count characters and compare.

Learning: Simple but builds foundation for harder problems.

💡 Reflection:
Today taught me how powerful two pointers, hashing, and string manipulation are. Even though these problems look different, they all circle back to basic concepts like sliding windows, frequency maps, and expansions.

I’m really enjoying documenting this journey because it makes me accountable, and I know after 150 days, looking back at these posts will feel amazing.

👉 Tomorrow, I’ll move forward with more string problems / maybe a mix of hash-based challenges.

If you’re also solving these, let me know how you approached them — would love to learn from your strategies! 🚀

100DaysOfCode #DSA #LeetCode #DevCommunity

🌟 Day 2 – Arrays Advanced (My 150 Days of DSA Journey)

Vrinda Khandelwal — Sat, 23 Aug 2025 18:07:22 +0000

Hey folks 👋

Today was Day 2 of my 150 Days of DSA Challenge, and honestly, this one felt like leveling up a bit compared to yesterday. The problems were trickier, more about thinking than just applying a formula. But that’s the fun part, right? 😊

🔥 What I solved today
1️⃣ Maximum Product Subarray (152)

This one was a rollercoaster.
At first, I thought, “Okay, just keep multiplying, what’s the big deal?” but then negative numbers entered the chat 😅.
The trick is: keep track of both the current max and min product, because a negative can flip the game.

2️⃣ Search in Rotated Sorted Array (33)

Classic interview problem!
It’s like binary search, but the array is all “rotated and twisted.” At least one side is always sorted, so the goal is figuring out which side to search in. Once you see that pattern → it’s smooth sailing. 🚤

3️⃣ Merge Intervals (56)

This felt kind of satisfying. You just sort all the intervals, then keep merging overlapping ones.
It’s like organizing a messy calendar into one neat schedule. 📅

4️⃣ First Missing Positive (41)

🔥 This one was tough.
The idea is to put every number at its “correct index” (like num should be at index = num-1). After rearranging, the first mismatch gives the answer. It took me a little while to get the intuition, but once it clicked, it felt magical ✨

5️⃣ Longest Consecutive Sequence (128)

Since I’m avoiding hash maps for now, I solved it with sorting.
Basically sort the array and just count streaks of consecutive numbers. Not the most optimal way, but it worked and gave me more clarity.

💭 Reflections

Today’s set pushed me out of my comfort zone.

I realized how much small tricks (like swapping min/max for negatives, or sorting before merging) can completely change the difficulty of a problem.

I’m actually starting to enjoy debugging my own wrong thoughts before hitting “Run” 😅

🚀 Next Steps

Tomorrow I’ll be moving to strings and palindrome problems.
I’m excited (and a bit scared) but that’s exactly why I’m doing this 150-day challenge — to push myself daily.

Thanks for reading! 🙌
If you’re also grinding DSA, let’s connect and cheer each other on. 💪

👉 This was my Day 2 update. On to Day 3 tomorrow!

🌟 Starting My 150 Days of DSA Journey – Day 1

Vrinda Khandelwal — Thu, 21 Aug 2025 20:20:14 +0000

Hello Everyone! 👋

I am starting my 150-day journey of Data Structures & Algorithms (DSA).
Every single day, I’ll solve problems and share my progress here. The goal is to build consistency, problem-solving skills, and strong fundamentals 💪.

✅ Problems I solved today (Day 1)
. Product of Array Except Self (LeetCode #238)

1.Two Sum (LeetCode #1)

Learned about brute force vs. optimized approaches.

Used hashmap approach for O(n) solution, but also practiced two pointers with sorting.

2.Best Time to Buy and Sell Stock (LeetCode #121)

Applied single-pass greedy approach.

Key idea: Track the minimum price so far and compute profit at each step.

3.Maximum Subarray (LeetCode #53)

Implemented Kadane’s Algorithm.

Learned how to track current sum vs. maximum sum efficiently.

4.Contains Duplicate (LeetCode #217)

Solved using a set to check duplicates in O(n) time.

5.Practiced the prefix-suffix product trick.

Learned to do it in O(n) without extra division.

✨ Reflections

Writing approaches in my copy helped me understand logic more clearly.

Even simple problems get tricky if not thought through carefully.

Excited to keep this momentum going for 150 days! 🔥

📌 Next Steps

Solve 4–5 problems daily (mix of easy & medium).

Keep documenting solutions + approaches.

Share progress consistently.

👉 Follow me here to keep track of my #150DaysOfDSA journey.
Let’s stay consistent and grow together 🚀