Minimum Time to Collect All Apples in a Tree - Leetcode 1443 - Python

[@MP-ny3ep]

Thank you for the daily leetcode problems. For beginners like me , its very helpful. You're a godsend.

[@FatCowFat]

thank you for explaining the daily leetcode problems 👍

[@arpanbanerjee6224]

you make things super easy! following your channel for a long time now....

[@shinewbiez]

Thank you so much for coming back to solve daily problems. These are very helpful! :D

[@laumatthew71]

Amazing solution and explanation, thank you !

[@picnicbros]

I was able to make it work with 53/54 but stuck for the last test case, and this video literally posted when I decided to seek help. Thank you!

[@NeetCodeIO]

I actually had the same issue as you I'm guessing 😅

[@arpanbanerjee6224]

@@NeetCodeIO Can you please tell me what was the issue. Or can you tell me the mistake in the code which resulted the last test case to fail

[@asmisrivastava3934]

@@arpanbanerjee6224 pass adjacency matrix by refrence and it will work

[@phaneendhrachinta7295]

Thanks for the Solution, clearly explained. !

[@readonlylogin]

Great explanation! I don't know python. And now I start thinning about learning python because realization is so cool!

[@CostaKazistov]

I did a double take when I saw the # of subscribers. Seemed off by a factor of 100. Now I get it.

[@krishnavamsi9326]

You are a great teacher bro! you changed my coding skills forever! Thank you very very much!😀

[@kapilchoudhary2922]

Beautiful explanation!!

[@rsKayiira]

Great solution and explanation. Only thing I wonder if using a visited hashset may have made the solution clearer

[@nihalbhandary162]

wouldnt matter it is a tree, all the nodes that will be visited could only be encountered once. ( you cant arrive at same vertex from 2 different paths in a tree because it would be a cycle).

[@TheSmashten]

Can you do the problem "Making A Large Island"?

[@xcampus]

welcome back neetcode.

[@Kilvny]

Thank you so much for your effort it DOES HELP ALOT

[@mohamedsalama2743]

this problem is part of the Trees section in your neetcode list where it should be part of Graphs

[@timmyfrank3]

agreed

[@xcampus]

please answer this question. if gennady korotkevich is for codeforce, __________________ is for leetcode? a, neetcode b,neetcode c,neetocode

[@kenmatsuru3470]

truely amazing!

[@krateskim4169]

Awesom explanation

[@shensean1784]

It has to be a noncyclic graph (tree).

[@nsandeep7574]

Good explanation

[@NeetCodeIO]

Glad to help!

[@imaadf5124]

Will you be posting all new leetcode videos on this channel?

[@NeetCodeIO]

Yes, all future LC videos

[@cj-nr5ni]

Nailed it

[@noahgsolomon]

Feel like this one should’ve been hard rated

[@parikshitjuneja]

C++ Solution for the same code class Solution { public: int minTime(int n, vector& edges, vector& hasApple) { vector adj(n); for (auto edge : edges) { adj[edge[0]].push_back(edge[1]); adj[edge[1]].push_back(edge[0]); } return dfs(0, -1, adj, hasApple); } int dfs(int curr, int parent, vector& adj, vector& hasApple) { int time = 0; for (auto child : adj[curr]) { if (child != parent) { int childTime = dfs(child, curr, adj, hasApple); if (childTime > 0 || hasApple[child]) { time += (childTime + 2); } } } return time; } };

[@ojaswiawasthi3645]

Hi !! Thank u so much for this solution !! But can u please can u solve this code by dry run. Actually I got stuck at dfs(4,1). I guess it should return 2 but I come across the continue statement ? :(

[@josnamohan9522]

Can anyone explain why was there a need to check if child == parent?

[@josnamohan9522]

@NeetCodeIO

[@basecase]

@@josnamohan9522 while creating adjajency list we are adding the same edge twice e.g. adj[0] has 1 and adj[1] also has 0 otherwise there will be an infinite loop.

[@josnamohan9522]

@@basecase Thanks for the explanation!

[@NeetCodeIO]

Yeah, Harsh answered it. You might think we don't need to add the edge twice, I did too, but the last test case will fail. Reason is that we need to be able to travel in both directions for this graph, even though it's a tree. And that test case has a child node, with two parents.

[@aakashgoswami2356]

This guy must be protected at any cost.

[@englishtechnique4813]

why not in java

[@baomao139]

It didn't work using the above code. I think line 17, it doesn't need to add 2 to every childTime. It should be t += childTime. If at least one childTime > 0 then t += 2 (only once )

[@dera_ng]

Omg

[@thomas_shelbyyt1349]

Big Fan of your work bro

[@NeetCodeIO]

Thank you 🙏