08/code.go

@@ -0,0 +1,138 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"math"
+	"os"
+	"sort"
+)
+
+type box struct {
+	x, y, z   int
+	id, best  int
+	inCircuit bool
+}
+
+func (p box) DistanceTo(other box) float64 {
+	dx := other.x - p.x
+	dy := other.y - p.y
+	dz := other.z - p.z
+	return math.Sqrt(float64(dx*dx + dy*dy + dz*dz))
+}
+
+func readInput(file *os.File) []box {
+	scanner := bufio.NewScanner(file)
+	var boxes []box
+	var id int
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if line == "" {
+			continue
+		}
+
+		var x, y, z int
+		n, err := fmt.Sscanf(line, "%d,%d,%d", &x, &y, &z)
+		if n != 3 || err != nil {
+			log.Fatalf("Bad input: %s", line)
+		}
+
+		boxes = append(boxes, box{x: x, y: y, z: z, id: id})
+		id++
+	}
+
+	return boxes
+}
+
+type circuit struct {
+	first, second int
+	boxes         []box
+}
+
+type distance struct {
+	first, second int
+	value         float64
+}
+
+func part1(boxes []box) int {
+	var result int
+	var distances []distance
+
+	for i := range boxes {
+		for j := i + 1; j < len(boxes); j++ {
+			howFar := boxes[j].DistanceTo(boxes[i])
+			distances = append(distances, distance{first: boxes[i].id, second: boxes[j].id, value: howFar})
+		}
+
+	}
+
+	sort.Slice(distances, func(i, j int) bool { return distances[i].value < distances[j].value })
+
+	var circuits [][]int
+	for i := range distances {
+		first := boxes[distances[i].first]
+		second := boxes[distances[i].second]
+		if first.inCircuit && second.inCircuit {
+			continue
+		}
+
+		if !first.inCircuit && !second.inCircuit {
+			circuits = append(circuits, []int{first.id, second.id})
+			boxes[distances[i].first].inCircuit = true
+			boxes[distances[i].second].inCircuit = true
+		} else if !first.inCircuit {
+			var found bool
+			for j := range circuits {
+				for k := range circuits[j] {
+					if circuits[j][k] == second.id {
+						found = true
+						circuits[j] = append(circuits[j], first.id)
+						break
+					}
+				}
+			}
+
+			boxes[distances[i].first].inCircuit = true
+			if !found {
+				circuits = append(circuits, []int{first.id})
+			}
+		} else if !second.inCircuit {
+			var found bool
+			for j := range circuits {
+				for k := range circuits[j] {
+					if circuits[j][k] == first.id {
+						found = true
+						circuits[j] = append(circuits[j], second.id)
+						break
+					}
+				}
+			}
+
+			boxes[distances[i].second].inCircuit = true
+			if !found {
+				circuits = append(circuits, []int{second.id})
+			}
+		}
+
+	}
+	fmt.Println(circuits)
+
+	return result
+}
+
+func main() {
+	if len(os.Args) < 2 {
+		log.Fatal("You need to specify a file!")
+	}
+
+	filePath := os.Args[1]
+	file, err := os.Open(filePath)
+	if err != nil {
+		log.Fatalf("Failed to open %s!\n", filePath)
+	}
+
+	boxes := readInput(file)
+	part1(boxes)
+}