Hello everyone,

I need help with the following problem E. Paired Payment.

I have read the tutorial but honestly I did not understand it much (maybe I am to blame for that), later I found a video by galen_colin on his youtube channel, the video link, He did an excellent job explaining problem E. However, he did not go into implementation details.

My question is:

• Is this some common technique used, if yes where can I read about it.
• How to plug these fake vertices into the graph and how to identify fake from original vertices? (I need the answer from implementation perspective)
• I also need similar problems to solve to strengthen my understanding with these kind of problems

I am looking for an answer, or maybe some blog where I can read about this technique more in details.

thanks in advance