How to code cleanly on observer pattern

Question

Refer code below:

I have a question on the said code.

Query 1 :

How can I have a cleaner or better code for below lines:
yt1.AddObserver(&h1);
yt1.AddObserver(&h2);
yt1.AddObserver(&h3);
h1.setSubject(&yt1);
h2.setSubject(&yt1);
h3.setSubject(&yt1);

Query 2:
How can I have channel name and video name into human class update method?
https://sololearn.com/compiler-playground/cpPj4yuEO2Fl/?ref=app