Is it possible to do an 1800 to 2000 sq foot roof in a day correctly?

when my parents had their roof done it took a long time.maybe a couple weeks altogether. it is a 3 bedroom cap cod. now where i live they are doing the roof in a day. all shingles removed and replaced. I can see 2 people working at the moment.
Update: there could be more people working. i just can only see 2 at the moment.
Update 2: OBVIOUSLY, i am aware the number of workers affects it as I mentioned the number.....and yes I am aware there are other factors such as pitch of roof and any unusual difficulties...
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