I’m surprised we’re not seeing any single-dose vaccines, there. There are some who only have one dose marked on the graph before they’re done, but those doses are all marked “2”, and are preceded by dotted lines, not the solid gray line used for undosed individuals.
And I’m not sure what’s supposed to be computationally difficult about this problem, with or without vaccines. It might get difficult if social events are so frequent that they often overlap, but these events appear to all be at least days apart.
I don’t think any of the dates were originally there. The problem included figuring what events you could do with whom at what time. There could easily be other events that were omitted.
I also think the NP-hard joke is just another self-deprecating joke about how bad Randal is in social situations.
Also, deciding it would be okay to watch the movie with person 3 is interesting. I presume they are counting on shot 1 immunity because this movie is something they’ve really been looking forward to, knowing the two other participants would be fully vaccinated. They’re taking a calculated risk.
That’s also what makes me think this might be an actual schedule for Randall’s real life. It would also explain why no single-shot users were included.
It’s a computer science term. There’s a certain class of problems where it is easy to check your answer, but hard to come up with a correct answer. For example, if I give you a set of objects of different weights, is there some subset that adds up to 100 lbs? Once you come up with a solution, it’s easy to verify. But there’s no known way to solve it other than trying all possible combinations. That and other problems are called NP-hard.
Informally, computer science types tend to use “NP-hard” as a kind of joke label for any difficult problem (like dealing with social anxiety). Also, it’s not possible for something to be “NP-hard enough”; it’s a binary classification.
Two fully-vaccinated people meeting with one partially-vaccinated person is probably safe enough… if it was just those three. Was the movie they were watching at home, or was it at a theater? If a theater, then yes, that one partially-vaccinated person was a non-negligible risk.
Once all people involved are vaccinated, though (as is the case in all but that one interaction), the risk should be very small in all cases. That doesn’t make for hard problems.
I was looking at some data that suggested that most of the people who took the J&J shot were younger adults. People whose lives are busy, and for whom “one shot, less protection” seems like a good trade-off. Randall is a little older, and my guess is that he and most of his friends got the 2-shot vaccines.
I think there’s a simpler explanation for an age bias in which shot people got. When older folks became eligible, the mRNA vaccines were the only ones available. Now, when young people are eligible, J&J is available, and due to its much easier logistics (easier to make, store, and transport), most vaccines are J&J. Old people can also get J&J now, of course, but many of those who would be interested already got Moderna or Pfizer, so they don’t need it.