Didn't understand the editorial of bottom view

#1

i don’t know the basics of maps and how it works so i didn’t understand the editorial provided.
plz can you explain me how map is used here, i got the concept of bottom up but failing to understand how map of int and pair<int,int> is used

#2

hello @Nishant_08

i would recommend to watch map and pair from stl playlist of ur course (hardly take 30 min ).