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+--- Day 8: Playground ---
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+-------------------------
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+
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+Equipped with a new understanding of teleporter maintenance, you confidently step onto the repaired teleporter pad.
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+
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+You rematerialize on an unfamiliar teleporter pad and find yourself in a vast underground space which contains a giant playground!
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+
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+Across the playground, a group of Elves are working on setting up an ambitious Christmas decoration project. Through careful rigging, they have suspended a large number of small electrical [junction boxes](https://en.wikipedia.org/wiki/Junction_box).
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+
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+Their plan is to connect the junction boxes with long strings of lights. Most of the junction boxes don't provide electricity; however, when two junction boxes are connected by a string of lights, electricity can pass between those two junction boxes.
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+
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+The Elves are trying to figure out *which junction boxes to connect* so that electricity can reach *every* junction box. They even have a list of all of the junction boxes' positions in 3D space (your puzzle input).
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+
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+For example:
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+
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+```
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+162,817,812
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+57,618,57
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+906,360,560
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+592,479,940
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+352,342,300
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+466,668,158
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+542,29,236
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+431,825,988
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+739,650,466
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+52,470,668
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+216,146,977
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+819,987,18
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+117,168,530
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+805,96,715
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+346,949,466
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+970,615,88
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+941,993,340
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+862,61,35
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+984,92,344
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+425,690,689
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+```
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+
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+This list describes the position of 20 junction boxes, one per line. Each position is given as `X,Y,Z` coordinates. So, the first junction box in the list is at `X=162`, `Y=817`, `Z=812`.
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+
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+To save on string lights, the Elves would like to focus on connecting pairs of junction boxes that are *as close together as possible* according to [straight-line distance](https://en.wikipedia.org/wiki/Euclidean_distance). In this example, the two junction boxes which are closest together are `162,817,812` and `425,690,689`.
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+
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+By connecting these two junction boxes together, because electricity can flow between them, they become part of the same *circuit*. After connecting them, there is a single circuit which contains two junction boxes, and the remaining 18 junction boxes remain in their own individual circuits.
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+
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+Now, the two junction boxes which are closest together but aren't already directly connected are `162,817,812` and `431,825,988`. After connecting them, since `162,817,812` is already connected to another junction box, there is now a single circuit which contains *three* junction boxes and an additional 17 circuits which contain one junction box each.
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+
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+The next two junction boxes to connect are `906,360,560` and `805,96,715`. After connecting them, there is a circuit containing 3 junction boxes, a circuit containing 2 junction boxes, and 15 circuits which contain one junction box each.
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+
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+The next two junction boxes are `431,825,988` and `425,690,689`. Because these two junction boxes were *already in the same circuit*, nothing happens!
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+
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+This process continues for a while, and the Elves are concerned that they don't have enough extension cables for all these circuits. They would like to know how big the circuits will be.
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+
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+After making the ten shortest connections, there are 11 circuits: one circuit which contains *5* junction boxes, one circuit which contains *4* junction boxes, two circuits which contain *2* junction boxes each, and seven circuits which each contain a single junction box. Multiplying together the sizes of the three largest circuits (5, 4, and one of the circuits of size 2) produces `40`.
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+
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+Your list contains many junction boxes; connect together the *1000* pairs of junction boxes which are closest together. Afterward, *what do you get if you multiply together the sizes of the three largest circuits?*
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+
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+--- Part Two ---
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+----------------
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+
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+The Elves were right; they *definitely* don't have enough extension cables. You'll need to keep connecting junction boxes together until they're all in *one large circuit*.
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+
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+Continuing the above example, the first connection which causes all of the junction boxes to form a single circuit is between the junction boxes at `216,146,977` and `117,168,530`. The Elves need to know how far those junction boxes are from the wall so they can pick the right extension cable; multiplying the X coordinates of those two junction boxes (`216` and `117`) produces `25272`.
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+
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+Continue connecting the closest unconnected pairs of junction boxes together until they're all in the same circuit. *What do you get if you multiply together the X coordinates of the last two junction boxes you need to connect?*
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