Hi everybody! I have no math background and I need the ans to this question, I'd really appreciate your help.
Everytime a new person enters a room all the people that are already in the room shake hands with everybody in the room. people come in one by one. if N people entered the room how many hand shakes were made?
I kinda get how the algorithm should go but I don't know how to write the answer as a function (maybe using the sum char)