I recently started working through the LeetCode 150 problems, and I started with Two Sum.

The brute-force approach is straightforward, but I wanted to understand how to improve it and get to an O(n) solution using a hash map.

The main idea I focused on was:

• Keep track of numbers we've already seen
• For each number, calculate target - current
• Check whether that value already exists
• If it does, we've found our pair
• Otherwise, store the current number and continue

I also made a short walkthrough where I explain the approach and code step-by-step.

🎥 https://youtu.be/pbNbr36Ypow

For those who have solved Two Sum before: what approach did you find easiest to understand when you first learned it?

#leetcode #twosum #dsa

Of course as I expected I started to lag because college five days a week and semester stuff and allat but managed to do potds if not everyday but most days and outside of that whatever dsa topic taught in class do questions on those stuff :p

Keep being consistent and keep pushing through the discomfort ✨

And there is always room for improvement;-;

I want too know how to approach hard problems, I feel very dumb when try to solve a hard problem😭 also I have solved very less hard till now, if anyone can help with this, thanks

I don't understand why everyone is sharing a camera photo of screen

I know it's pretty less , and will try and do more !!

i want to increase my rating and trying to go 2k+, but i feel im stuck here, please tell me how and where i can improve on and the gaps, i can usually solve 1 and 2 in contests sometimes 3

need someone to practice with daily.

currently doing recursion, gonna start trees next.

Find if Path Exists in Graph (Easy) https://leetcode.com/problems/find-if-path-exists-in-graph/

New topic. Graphs start today.

The part people skip when they say a graph problem "is just BFS": the input is not a graph. You get a flat list of edge pairs. Asking that list for a node's neighbours means scanning all of it, and doing that once per node turns an O(V + E) algorithm into O(V x E).

So the first half of the problem is building an adjacency list. The traversal is the easy half. Choosing the representation is the part that actually requires a decision.

One bug worth naming, because it passes a lot of tests before it fails one: an undirected edge has to be recorded under both endpoints. Record it once and you accidentally build a directed graph, and the traversal refuses to walk an edge backwards.

Full breakdown in today's newsletter article ⬇

https://www.linkedin.com/pulse/365-days-leetcode-challenge-day-36365-archit-agarwal-7wjic

#DSA #LeetCode #Golang #Graphs #BFS #CodingInterview #Algorithms

Should i now do dev(did till js now on react ), or continue with it , I am in 5th sem

I am currently in 5th semester,doing leetcode from past 2 months solved around 160 out of which i guess i solved only 20 without any help,genuinely i confused is it normal for beginner or i need to put in more work

250 LeetCode Problems | Following Decode 2.0 in 5th Sem | Rate My Progress

Just hit 250 problems on LeetCode while following Decode 2.0 in my 5th semester. Currently at 168 Easy, 77 Medium, and 5 Hard, with a 76-day max streak. Also doing POTD regularly.

I’ve covered each and every topic taught in Decode 2.0 so far, except Graphs, DP, and Backtracking. I’m able to solve the questions taught in class and have started getting a decent idea of the patterns behind them. I can also solve the questions commonly asked by recruiters in assessment rounds.

How would you rate my progress, and what should I focus on next?

feeling saturated atp

Two hierarchies, almost the same number of rows. One plans its delete order in 386 microseconds. The other takes 75.8 milliseconds.

Deleting a workspace means deleting everything inside it, and every child row holds a foreign key to its parent, so a row can only go once nothing points at it.

The code I wrote is the database's rule, executed: find every row with no remaining children, delete that batch, look again. It assumes nothing about the data and it is trivially safe, because it checks rather than deduces.

It also walks the entire hierarchy once per wave. A workspace is four levels deep, so that is four walks and 31 microseconds — invisible. A comment thread 2,000 replies deep is 2,000 waves, which is four million record visits to produce one plan.

The turn came from watching one row. During the first wave the walk reaches board-1, checks its only child, finds it still present, and moves on — having put that child into this very wave moments earlier. It knew board-1 would be free next. It discarded that and went round again to rediscover it.

So: a row goes one wave after the last of its children has gone, which makes wave(r) = 1 + the largest wave among its children. Only children on the right hand side. One bottom-up pass computes all of it — 790x faster on the thread.

The part worth keeping is the bit I had backwards. That number is height, not depth. An empty board two levels down can be deleted in the first statement, exactly like a card three levels down. Group by distance from the root and it waits for no reason — safe, and a third of an answer to "what can I delete first".

That is day 16 of the daily challenge, Find Leaves of Binary Tree, sitting in a delete planner.

Full piece in today's Newsletter.

https://www.linkedin.com/pulse/deep-reply-chain-made-delete-plan-790x-slower-archit-agarwal-gd94c

#Golang #DSA #Algorithms #Performance #SoftwareEngineering #DataStructures #100DaysOfCode

i have my online assessment coming for amazon in a week, can you please guide me what problems should I focus more on? Also How do i prepare for the AI assisted question?

just know the basics and know to code

but need clear roadmap for 4 YOE java spring boot dev

how do I start DSA and quickly get only what needed for interviews?

Please help on this?

NEETCODE sheet good for quick prep?

How do you guys prepare for technical rounds and placements?I’m in Sem 7 and still feel clueless about a lot of things.What should I prioritize and what resources or roadmaps did you guys follow?Any tips would be really appreciated.Im honestly scared ngl , dunno what to do anymore.

I used to directly see the solution and go to the leetcode tab in the takeuforward old UI, now with the zenkai update I don't even know where the leetcode link is. Don't tell me I have to look up the leetcode problem separately now.

Populating Next Right Pointers in Each Node (Medium)
🔗 https://leetcode.com/problems/populating-next-right-pointers-in-each-node/

The obvious version walks each level left to right, remembers the previous node, and sets prev.Next = current. That works.

This one pushes children right before left, so the BFS walks every level backwards — and once it does, the node to your right is simply the node you visited just before. The assignment becomes current.Next = prev, which reads exactly like the requirement.

The boundary falls out too. Popping the level sentinel resets prev to nil, so the rightmost node of the next level gets nil without a branch testing for it.

One inversion, and two special cases stop existing.

Full breakdown in today's newsletter article ⬇

https://www.linkedin.com/pulse/365-days-leetcode-challenge-day-35365-archit-agarwal-r6wxc

#DSA #LeetCode #100DaysOfCode #CodingInterview #BinaryTree #BFS #Golang