93 lines
1.9 KiB
Markdown
93 lines
1.9 KiB
Markdown
## \-\-- Day 23: LAN Party \-\--
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As The Historians wander around a secure area at Easter Bunny HQ, you
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come across posters for a [LAN
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party](https://en.wikipedia.org/wiki/LAN_party)
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scheduled for today! Maybe you can find it; you connect to a nearby
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[datalink port](/2016/day/9) and download a map of the local network
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(your puzzle input).
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The network map provides a list of every *connection between two
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computers*. For example:
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kh-tc
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qp-kh
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de-cg
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ka-co
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yn-aq
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qp-ub
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cg-tb
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vc-aq
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tb-ka
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wh-tc
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yn-cg
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kh-ub
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ta-co
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de-co
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tc-td
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tb-wq
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wh-td
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ta-ka
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td-qp
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aq-cg
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wq-ub
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ub-vc
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de-ta
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wq-aq
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wq-vc
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wh-yn
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ka-de
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kh-ta
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co-tc
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wh-qp
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tb-vc
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td-yn
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Each line of text in the network map represents a single connection; the
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line `kh-tc` represents a connection between the computer named `kh` and
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the computer named `tc`. Connections aren\'t directional; `tc-kh` would
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mean exactly the same thing.
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LAN parties typically involve multiplayer games, so maybe you can locate
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it by finding groups of connected computers. Start by looking for *sets
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of three computers* where each computer in the set is connected to the
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other two computers.
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In this example, there are `12` such sets of three inter-connected
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computers:
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aq,cg,yn
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aq,vc,wq
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co,de,ka
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co,de,ta
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co,ka,ta
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de,ka,ta
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kh,qp,ub
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qp,td,wh
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tb,vc,wq
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tc,td,wh
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td,wh,yn
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ub,vc,wq
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If the Chief Historian is here, *and* he\'s at the LAN party, it would
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be best to know that right away. You\'re pretty sure his computer\'s
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name starts with `t`, so consider only sets of three computers where at
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least one computer\'s name starts with `t`. That narrows the list down
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to `7` sets of three inter-connected computers:
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co,de,ta
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co,ka,ta
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de,ka,ta
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qp,td,wh
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tb,vc,wq
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tc,td,wh
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td,wh,yn
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Find all the sets of three inter-connected computers. *How many contain
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at least one computer with a name that starts with `t`?*
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To begin, [get your puzzle input](23/input).
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Answer:
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