There are some problems, particularly from old contests, whose editorial is hard to understand(as it is not explanatory enough) and leaves me clueless regarding step(s) in the editorial.

Posting a blog for every problem whose editorial I couldn't understand doesn't seem like a good way to ask for help.

Where should I ask for help in such cases? Is there any discord server/telegram channel/any other thing where other people are active and I can ask for help for problems rated 1700-1900 ?

I am using sublime text 3 with pre compiled headers as mentioned in this blog.

The build that I am using is as follows :

{
"cmd" : ["g++ -std=c++17 $file_name -o $file_base_name && timeout 4s ./$file_base_name <input.txt >stdout.txt 2>stderr.txt"], 
"selector" : "source.c",
"shell": true,
"working_dir" : "$file_path"
}

If I use <bits/stdc++.h>, it takes 1.2s to compile and run every time I run any code( eg. Hello World code) using Ctrl+B.

When I use "bits/stdc++.h" (and expect the compilation time to become less) it actually takes 5-6 s to compile and run even the "Hello World" program for the first time using Ctrl+B. From next time, it takes 0.3 s only but the first time, it takes as long as 5-6s.

For every new program that I write, it happens like this. For eg. If I change the "Hello World" program to print 10 numbers from 1-10, it will again take 5-6s to compile and run. Then from the second time, it will take 0.3-0.4 s.

The directory structure is as follows :

CP/

• bits/
  • stdc++.h
  • stdc++.h.gch
• code.cpp (this is the file in which I write the code)

I have tried finding some information online but couldn't find anything useful. Can someone please help me out?

Can someone please share their stress testing library?

I am looking for random tree, graph(connected/disconnected) generators and different type of array generators.

I recently found out that inserting a vector in a map is possible :

map< vector<int>, int > mp;
vector<int> vec = {1,2,3,4,5};
mp[vec] = 5;
cout<<mp[vec];
// prints 5

1. If there are N vectors in mp present as keys already, what is the time complexity to insert a new vector of size M in mp ? Is it O(M*log(N) or something else depending upon the sizes of vectors present in mp already?
2. What would be the time complexity of a query operation such as mp[vec]? Please help.

By what factor is Kosaraju's algorithm for finding strongly connected component slower as compared to Tarjan's algorithm. It appears to me that the factor should be 3 as there are 2 dfs passes in Kosaraju's algorithm and we also have to transpose the graph once. Am I missing something ?

Also is there any way to find the tranpose graph without declaring a new graph and storing the edges in reverse order ? (Basically reversal of graph without use of extra memory)