adventofcode/2025/day08/problem

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--- Day 8: Playground ---

   Equipped with a new understanding of teleporter maintenance, you
   confidently step onto the repaired teleporter pad.

   You rematerialize on an unfamiliar teleporter pad and find yourself in a
   vast underground space which contains a giant playground!

   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 [16]junction boxes.

   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.

   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).

   For example:

 162,817,812
 57,618,57
 906,360,560
 592,479,940
 352,342,300
 466,668,158
 542,29,236
 431,825,988
 739,650,466
 52,470,668
 216,146,977
 819,987,18
 117,168,530
 805,96,715
 346,949,466
 970,615,88
 941,993,340
 862,61,35
 984,92,344
 425,690,689

   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.

   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 [17]straight-line distance. In this example, the two junction boxes
   which are closest together are 162,817,812 and 425,690,689.

   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.

   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.

   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.

   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!

   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.

   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.

   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?

   To begin, [18]get your puzzle input.

   Answer: [19]_____________________ [20][ [Submit] ]

   You can also [Shareon [21]Bluesky [22]Twitter [23]Mastodon] this puzzle.

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