By derAdler, history, 3 years ago, ,

Hello friends, i know that there are a lot of similar blogs out there but i m writing this because of a genuine concern, i have been coding for sometime now but still i m unable to think beyond a certain level, however hard i try to, i don't know what to do, during holidays,i used to code for fun but since the holidays ended i do not feel like coding anymore, because so much time is wasted in daily chores and when i see people solving good questions i feel even more demotivated, i dont know what to do and i think i have forgotten whatever i learnt during holidays, i really want to code and increase my level and my lost confidence(which i gained during holidays) so guys plz help, for eg i m sure that i could have thought educational round 14 D question if i were the same person as during the holidays but i couldn't today, i lost even more confidence(i was trying to think topological sort or dsu or something but i was simply sorting), i just want to know a method to gain my lost confidence, plz help guys.. also i get demotivated when i see others writing some complex level code(compared to my simple but correct code), which i cannot understand....

• +3

By derAdler, history, 3 years ago, ,

Hello guys, I am trying hard to learn LCA and here are some good problems i found and i thought to share them

A great HackerRank tutorial: https://www.hackerrank.com/topics/lowest-common-ancestor

The Best Tutorial i encountered so far: http://csengerg.github.io/2015/12/24/lowest-common-ancestor.html

If you have more good problems or tutorials that you can share, share them in the comments.

EDIT: Guys, could you plz share problems on SCC and where can i find it's tutorial, blog etc.

• +29

By derAdler, history, 3 years ago, ,

hello guys, i know this might sound silly. I was just studying trie the other day and i wanted to ask that why do we use it at all we can maintain a directed graph of 26*26 where G[i][j] corresponds to whether j is a child of letter i. Could somebody explain how i am wrong with an example. Any help would be appreciated. Thanks a lot in advance.

• -24

By derAdler, history, 3 years ago, ,

Could someone explain me the proof of this line: "Let l hasn't right child and r hasn't left child. Hence lowest common ancestor (lca) of l and r doesn't equal to l or r. So lca is between l and r in tree traversal. But it's impossible because l is maximal possible and r is minimal possible. So l has right child or r has left child and we know exactly which of them will be parent of x." in the problem tree construction (link: http://codeforces.com/problemset/problem/675/D) also could you plz suggest some SCC and LCA problems.