2025 Day 8 Complete

2025/day08/main.go

@@ -0,0 +1,83 @@
+package main
+
+import (
+	"cmp"
+	"fmt"
+	"maps"
+	"slices"
+	"strings"
+
+	h "git.bullercodeworks.com/brian/adventofcode/helpers"
+)
+
+func main() {
+	inp := h.StdinToStringSlice()
+	solve(inp)
+}
+
+func solve(inp []string) {
+	var part1, part2 int
+	pts := inputToMap(inp)
+	circuits := []map[h.Coordinate3d]struct{}{}
+	for _, b := range pts {
+		circuits = append(circuits, map[h.Coordinate3d]struct{}{b: {}})
+	}
+
+	pairs := [][2]h.Coordinate3d{}
+	for i, b1 := range pts {
+		for _, b2 := range pts[i+1:] {
+			pairs = append(pairs, [2]h.Coordinate3d{b1, b2})
+		}
+	}
+	slices.SortFunc(pairs, func(a, b [2]h.Coordinate3d) int {
+		return cmp.Compare(a[0].Distance(a[1]), b[0].Distance(b[1]))
+	})
+
+	for i, p := range pairs {
+		var c1, c2 int
+		for i, c := range circuits {
+			if _, ok := c[p[0]]; ok {
+				c1 = i
+			}
+			if _, ok := c[p[1]]; ok {
+				c2 = i
+			}
+		}
+
+		if c1 != c2 {
+			maps.Copy(circuits[c1], circuits[c2])
+			circuits = slices.Delete(circuits, c2, c2+1)
+		}
+
+		if i+1 == 1000 {
+			slices.SortFunc(circuits, func(a, b map[h.Coordinate3d]struct{}) int {
+				return -cmp.Compare(len(a), len(b))
+			})
+			part1 = len(circuits[0]) * len(circuits[1]) * len(circuits[2])
+		}
+		if len(circuits) == 1 {
+			part2 = (p[0].X * p[1].X)
+			break
+		}
+	}
+	fmt.Println("# Part 1")
+	fmt.Println(part1)
+	fmt.Println()
+	fmt.Println("# Part 2")
+	fmt.Println(part2)
+}
+
+func inputToMap(inp []string) []h.Coordinate3d {
+	var ret []h.Coordinate3d
+	for i := range inp {
+		pts := strings.Split(inp[i], ",")
+		ret = append(ret,
+			h.Coordinate3d{
+				X: h.Atoi(pts[0]),
+				Y: h.Atoi(pts[1]),
+				Z: h.Atoi(pts[2]),
+			},
+		)
+	}
+	return ret
+}

2025/day08/problem

@@ -0,0 +1,140 @@
+                               [1]Advent of Code
+
+     • [2][About]
+     • [3][Events]
+     • [4][Shop]
+     • [5][Settings]
+     • [6][Log Out]
+
+   br0xen [7](AoC++) 14*
+
+                                  <y>[8]2025</y>
+
+     • [9][Calendar]
+     • [10][AoC++]
+     • [11][Sponsors]
+     • [12][Leaderboards]
+     • [13][Stats]
+
+   Our [14]sponsors help make Advent of Code possible:
+   [15]Kilo Code - The fastest growing coding agent because it is open. #1 on
+   OpenRouter. 500k+ Kilo Coders. 6.1T tokens per month. Try it today!
+
+--- 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.
+
+References
+
+   Visible links
+   1. https://adventofcode.com/
+   2. https://adventofcode.com/2025/about
+   3. https://adventofcode.com/2025/events
+   4. https://adventofcode.com/2025/shop
+   5. https://adventofcode.com/2025/settings
+   6. https://adventofcode.com/2025/auth/logout
+   7. Advent of Code Supporter
+	https://adventofcode.com/2025/support
+   8. https://adventofcode.com/2025
+   9. https://adventofcode.com/2025
+  10. https://adventofcode.com/2025/support
+  11. https://adventofcode.com/2025/sponsors
+  12. https://adventofcode.com/2025/leaderboard/private
+  13. https://adventofcode.com/2025/stats
+  14. https://adventofcode.com/2025/sponsors
+  15. https://adventofcode.com/2025/sponsors/redirect?url=https%3A%2F%2Fkilo%2Eai%2F
+  16. https://en.wikipedia.org/wiki/Junction_box
+  17. https://en.wikipedia.org/wiki/Euclidean_distance
+  18. https://adventofcode.com/2025/day/8/input
+  21. https://bsky.app/intent/compose?text=%22Playground%22+%2D+Day+8+%2D+Advent+of+Code+2025+%23AdventOfCode+https%3A%2F%2Fadventofcode%2Ecom%2F2025%2Fday%2F8
+  22. https://twitter.com/intent/tweet?text=%22Playground%22+%2D+Day+8+%2D+Advent+of+Code+2025&url=https%3A%2F%2Fadventofcode%2Ecom%2F2025%2Fday%2F8&related=ericwastl&hashtags=AdventOfCode
+  23. javascript:void(0);

2025/day08/testinput

@@ -0,0 +1,20 @@
+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

helpers/coordinate3d.go

@@ -1,6 +1,9 @@
 package aoc
 
-import "fmt"
+import (
+	"fmt"
+	"math"
+)
 
 type Coordinate3d struct {
 	X, Y, Z int
@@ -71,6 +74,13 @@ func (c *Coordinate3d) GetDownCoord() *Coordinate3d {
 		Z: c.Z - 1,
 	}
 }
+
+func (c *Coordinate3d) Distance(c2 Coordinate3d) float64 {
+	return math.Sqrt(math.Pow(float64(c2.X-c.X), 2) +
+		math.Pow(float64(c2.Y-c.Y), 2) +
+		math.Pow(float64(c2.Z-c.Z), 2))
+}
+
 func (c Coordinate3d) String() string {
 	return fmt.Sprintf("[X:%d, Y:%d, Z:%d]", c.X, c.Y, c.Z)
 }