LeetCode Merge Two Binary Trees Solution Explained - Java

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#coding #programming #softwareengineering

[@basedonprinciple]

Thanks for the tip about doing the 40 tree problems at the end.

[@ConwellConwell]

Nick helped code 911 and grinder

[@Kitchen-Raccoon4572]

Bring back this Nick White. The cool chill one that just helps out

[@sadmanabedin1203]

got the logic and solved the problem just after 3:27. thanks bro.

[@muscle_coder]

Great Work bro Can you make a basic lecture on Binary Tree explaining the traversals with dry run in Trees ?

[@abhaypatil2000]

The problem you mentioned is not with leetcode. The problem is with multithreading at hardware level. Executing same program multiple times, will result in different time.

[@mdaminulhoque1707]

line 23, it should be t1.right = mergeTrees(t1.right, t2.right);

[@snake1625b]

oh i thought you had to insert all the nodes from the right into the left tree, not add the overlapping ones. should've read the question

[@jay31415]

This question is awkwardly and ambiguously worded-a pattern I've noticed in LeetCode tree questions-as evidenced by bad grammar in the first sentence. The entire question would have been better off just showing the example on its own, ditching the misleading wording, instead simply saying "do this".

[@Emmanuel-px9lk]

Very clear. Thanks

[@xbeta84]

This is mine, similar to yours, but I don't merge into t1 to make it more readable def merge_trees(t1, t2): """ :type t1: TreeNode :type t2: TreeNode :rtype: TreeNode """ if t1 == None: return t2 if t2 == None: return t1 node = TreeNode(t1.val + t2.val) node.left = merge_trees(t1.left, t2.left) node.right = merge_trees(t1.right, t2.right) return node

[@boshiij3449]

This is good but the interviewer might ask to reduce space by merging in-place instead of creating a new binary tree. Good to know and understand both though.

[@noctua7771]

You are brilliant good sir!

[@TheodoreRavindranath]

For an experienced developer, this looks scary.. because we prefer immutability, and clean copies. All this t1.val+=t2.val thereby mutating the input tree, and just grabbing some nodes off another tree and keeping them in our tree... all this looks scary!!

[@bigblue82]

Agreed! When I first attempted this I assumed (wrongly, but based on experience) that the input trees should not be mutated. So I created an entire new tree and left the input trees untouched which made my solution more complicated. This one is far more simple, but it mutates t1 which feels so gross to me.

[@vishwajeetbarve6538]

Clean and Simple

[@DEEPAKGOYALnullRA]

why this problem is in easy level its looking too difficult man

[@botdot7226]

Yeah I agree. My theory is that it rates the problems based on the % accepted rate. As you can see 136k/200k submissions passed meaning ~68% completed this problem. However, this is problem 617 meaning that only really dedicated users will have attempted this problem as fewer people will have likely made it past the first couple questions. Therefore, in this 200k is likely to be very experienced coders so the difficulty rating is misleading.

[@spectermakoto9029]

you have to really understand cs fundamentals not a difficult problem if you do have problems i recommend you brush up on trees and recursion

[@jugsma6676]

This is just the DFS traversal of the tree.

[@sarf_alam]

wait why is he not indian😂😂?

[@isanrodrigueztrimino6701]

28 of January of 2023. Leetcode hasn't fix that yet

[@cocoarecords]

ty

[@eshagupta9407]

You rock, Thanks!

[@spinacker16]

it's soooo easy =( But I cant solve even that problem... what's wrong with me GOD DAMN

[@cartooncartel6493]

I hate it when he says that