Accounts Merge - Leetcode 721 - Python

0:00 - Read the problem
0:50 - Drawing Explanation
10:10 - Coding Explanation

leetcode 721

#neetcode #leetcode #python

[guilhermezardo]

Definitely not a medium problem. Should be a hard problem in my opinion...

[DavidDLee]

Interesting solution to use the account index as the nodes being joined in the graph.
I too used a Union-Find solution but used the email strings as the nodes instead. Using the index, it is pretty trivial to find the name. In my solution, I needed a map from parent -> name.
Part of the problem is that Union-Find provides as output a non-useful child -> parent tree, which you need to invert into parent -> children.
The last loop can be done using list comprehension in one line.

[technophile_]

I'm just happy that I'm able to at least understand the terminologies used in this video 😅

[huzayfasabri]

Wait what was the time and space complexity?

[atreides]

What a coincidence, I was working on this one. Are you doing grind75 problems now??

[kacpermodkowski]

Your videos are great and you explain everything very well. I am not sure if that is just me, but oftentimes I am confused by your variable names. Great example is 14:31 you turned "email" variable name to "e" that with "i" emailToAcc (why not simply emailToAccount?). Maybe it is just me, but that makes it more difficult in my opion to follow along and read the solution.

[krishnasharma]

The neatness of ur code makes u neetcode😊

[subikeshps]

10:52 I don't understand how union find operations take only constant time? Worst case would be log n isn't it?

[anishkarthik]

please make solutions for leetcode weekly contests here onwards if possible please, your explanations are very easy and understandable. No one on YouTube explains better than you.

So I can learn to solve weekly problems

[kyoungjunhan]

Solved this problem like 3 days ago. It was a pain in the butt to get my head around using dfs with two different references.

[sumitsharma]

Bro make videos on leetcode contests too

[devenderbhatt]

It would be better if u link ur union find explanation video in description itself very hectic to find that in ur old library😢

[pacomarmolejo]

Love your vids bro. Is the time complexity O(NKlogK) where N accounts, K max-emails in an account, as for the DFS solution?

[ayushbhardwaj]

Cann't we just use DFS instead of using disjoint sets. ? Whats the efficiency in using disjoint sets, anyways we have to traverse all connected components.

[Daniel-domh]

Hi man! Move your content and thank you very much for helping us! Would love if u could also make playlists here of "Easy", "Medium" and "Hard" related to how the leetcode problems solved in the videos are.

[subhaspaul]

please make solutions for leetcode weekly contests

[les_grossman]

This is the most crack head of crack head problems that I've run into in my humble opinion. Just because it's commonly asked in Big Tech interviews doesn't mean it should be ranked as a medium, more so a very common hard problem.

[LiadMotorin]

@NeetCode what is the time&space complexity ?

[alentino_woo]

The path compression of find() in your code is not actually compressing path, here is the one that actually compress:
def find(self, node):
# Path Compression
parentIdx = self.parents[node]
while parentIdx != self.parents[parentIdx]:
parentIdx = self.parents[parentIdx]
self.parents[node] = parentIdx
 return parentIdx