I managed to work in, this weekend, reading a young adult book by Veronica Roth, Divergent.
It takes place in a post-apocalyptic Chicago (and I was glad to have been in Chicago this summer, as it got me to recognize several places) where the city still (kind of) exists next to a big marsh that used to be Lake Michigan. In response to the destruction of society, the people have been split into five groups, each of which emphasizes one trait that that group believed contributed to the End. Those groups are Abnegation (selflessness), Amity (peacefulness), Candor (honesty), Dauntless (fearlessness), and Erudite (knowledge).
Everyone, on a specific date around their sixteenth birthday, has to take an aptitude test to determine which group they're most cut out for (and it seems that most people end up staying in the group in which they were born). Shortly after (I think it was a couple of days later), they choose which group they want to be in.
But some people are shown to be Divergent by the aptitude test (which is administered VR-like via a serum). Few people are quite sure what it means, but it's deadly to admit to (for reasons unclear until very late in the book).
The main character, Beatrice, is born to an Abnegation family, and is found to be Divergent. The test-giver didn't rat on her for being Divergent, and allows her to make her own choice after telling her that the test ruled out two factions.
She chooses Dauntless, and is thrown into a bit of a nightmare of initiation, as Dauntless (at least as it is "today") is very Darwinian (and, yes, cutthroat). It takes a while to come out, but the Dauntless are the ones that protect the city from the outside, although we never really find out from what they're protecting the city. They are the only group that has firearms, although they don't seem to have a lot of them.
So you can see where there are a lot of parallels with Hunger Games (more than I expected, when I started it); I think the main character is, also like in Hunger Games, becoming one of the driving forces of a revolution overturning society, although I don't have the second book to confirm that. (Which reminds me, I still haven't seen the second Hunger Games movie. Need to rectify that.)
The book definitely has some problems; learning to use a gun takes (much) more than a day or two. And learning to fight, hand-to-hand, takes much longer yet. Expecting a group that has never done either to be able to compete with people who've been doing it all their lives is absurd.
And let's face it, if there are only twenty-ish new people each year joining a group of ... well, it's unclear, but seems to at least be several hundred to a thousand... Well, that won't be enough. Especially after that group is cut down to ten.
Plus, it takes quite a few support people to keep an army running. It wouldn't take nearly as many as today's US Army (which has, IIRC over a hundred support per soldier), but it's considerably more than zero.
And that doesn't even touch on the number of Erudite. To manufacture the things briefly mentioned takes very large numbers of people. You need the people to do the designing, then the people to design the manufacturing, then the people to do the manufacture, then the people to assure the power for all of those stages, the training people to teach the engineers, etc. It would take hundreds of times the number of Dauntless (although it's possible that there are far more Erudite than Dauntless, it's very unlikely).
Actually, that is one dynamic that isn't even touched on; the relative sizes of the various factions.
One that is discussed is that the government is almost entirely run by Abnegation; the other factions have only token representation. This does make sense, in a way; you do get the least corrupt people running things. And in a low-resource environment, that's certainly important.
Anyway, it's a very interesting book, and will probably make a pretty decent movie (it's coming in March), but I'm undecided about whether I'm going to read any more of it. Maybe I'll get them from the library. One thing strongly in its favor was that I raced through it in very little time, so it definitely kept my attention (much more difficult, these days, than it used to be).