If you didn’t know already, Google holds these competitions for coding that happen around the world every year. In 2017’s HashCode Competition, a qualification problem was given to the people who wanted to qualify for the competition.
Videos are a lot of data and you can’t have cache servers as big as your main data center servers — the costs would be horrendous.
If it is, it doesn’t store again making sure that the space is available if another video is better stored in that cache as well.
This is to check another skillset which is stream-writing, where the iteration you write the data in and the form you do it in, is IMPORTANT.