day 8 part 1 & 2

8/solve_1.go

@@ -0,0 +1,118 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"math"
+	"os"
+	"slices"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+func main(){
+	fmt.Println("Advent of Code 2025 - Day 8 - Part 1")
+	f,_:=os.Open("8/input")
+	defer f.Close()
+
+	var junction_boxes [][]int64
+	
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan(){
+		line := scanner.Text()
+		var coords []int64
+		for c := range strings.SplitSeq(line, ","){
+			c_i,_ := strconv.ParseInt(c,10,64)
+			coords = append(coords, c_i)
+		}
+		junction_boxes = append(junction_boxes, coords)
+	}
+	distances := calculate_distances(junction_boxes)
+	top3_circuits := create_circuits(1000, distances)[:3]
+	res := 1
+	for _,c := range top3_circuits{
+		res *= c
+	}
+	fmt.Println(res)
+}
+
+func create_circuits(nb_connections int, distances sj_box_distances) []int {
+	var circuits [][]int
+	circuits = append(circuits, []int{distances[0].b1, distances[0].b2})
+	for i := 1; i < nb_connections; i++ {
+		b1,b2 := distances[i].b1, distances[i].b2
+		new := true
+		for cir := range circuits {
+			ok1, ok2 := slices.Contains(circuits[cir],b1), slices.Contains(circuits[cir],b2)
+			if ok1 && ok2 {
+				new = false
+				break
+			} else if ok1 && !ok2 {
+				new = false
+				merge_circuits(cir, b2, &circuits)
+				break
+			} else if !ok1 && ok2 {
+				new = false
+				merge_circuits(cir, b1, &circuits)
+				break
+			}
+		}
+		if new {
+			circuits = append(circuits, []int{b1,b2})
+		}
+	}
+	
+	var res []int
+	for _,c := range circuits{
+		res = append(res, len(c))
+	}
+	sort.Sort(sort.Reverse(sort.IntSlice(res)))
+	return res
+}
+
+func merge_circuits(idx_cir, box int, circuits* [][]int) {
+	idx_cir_tomerge := -1
+	for i := range *circuits{
+		if slices.Contains((*circuits)[i],box){
+			idx_cir_tomerge = i
+		}
+	}
+	if idx_cir_tomerge >= 0 {
+		(*circuits)[idx_cir] = append((*circuits)[idx_cir], (*circuits)[idx_cir_tomerge]...)
+		(*circuits)[idx_cir_tomerge] = (*circuits)[len(*circuits)-1]
+		(*circuits) = (*circuits)[:len(*circuits)-1]
+	} else {
+		(*circuits)[idx_cir] = append((*circuits)[idx_cir], box)
+	}
+}
+
+type j_box_distance struct {
+	b1,b2 int
+	dis float64
+}
+
+type sj_box_distances []j_box_distance
+
+func (a sj_box_distances) Len() int { return len(a)}
+func (a sj_box_distances) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
+func (a sj_box_distances) Less(i, j int) bool { return a[i].dis < a[j].dis }
+
+
+func calculate_distances(points [][]int64) sj_box_distances {
+	var res sj_box_distances
+	for i := range(points) {
+		for j := i+1; j < len(points); j++{
+			b1,b2 := i,j
+			dis := euclidiean_distance(points[i],points[j]) 
+			res = append(res, j_box_distance{b1,b2,dis})
+		}
+	}
+	sort.Sort(res)
+	return res
+}
+
+func euclidiean_distance(p1, p2 []int64) float64 {	
+	dx,dy,dz := math.Pow(float64(p1[0] - p2[0]), 2.0), math.Pow(float64(p1[1] - p2[1]), 2.0), math.Pow(float64(p1[2] - p2[2]), 2.0)
+	return math.Sqrt(dx + dy + dz)
+}

8/solve_2.go

@@ -0,0 +1,115 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"math"
+	"os"
+	"slices"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+func main(){
+	fmt.Println("Advent of Code 2025 - Day 8 - Part 1")
+	f,_:=os.Open("8/input")
+	defer f.Close()
+
+	var junction_boxes [][]int64
+	
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan(){
+		line := scanner.Text()
+		var coords []int64
+		for c := range strings.SplitSeq(line, ","){
+			c_i,_ := strconv.ParseInt(c,10,64)
+			coords = append(coords, c_i)
+		}
+		junction_boxes = append(junction_boxes, coords)
+	}
+	distances := calculate_distances(junction_boxes)
+	b1,b2 := create_circuits(distances, len(junction_boxes))
+	res := junction_boxes[b1][0] * junction_boxes[b2][0]
+	fmt.Println(res)
+}
+
+func create_circuits(distances sj_box_distances, nb_jb int) (int,int) {
+	res1,res2 := 0,0
+	var circuits [][]int
+	circuits = append(circuits, []int{distances[0].b1, distances[0].b2})
+	for i := 1; i < len(distances); i++ {
+		b1,b2 := distances[i].b1, distances[i].b2
+		new := true
+		for cir := range circuits {
+			ok1, ok2 := slices.Contains(circuits[cir],b1), slices.Contains(circuits[cir],b2)
+			if ok1 && ok2 {
+				new = false
+				break
+			} else if ok1 && !ok2 {
+				new = false
+				merge_circuits(cir, b2, &circuits)
+				break
+			} else if !ok1 && ok2 {
+				new = false
+				merge_circuits(cir, b1, &circuits)
+				break
+			}
+		}
+		if new {
+			circuits = append(circuits, []int{b1,b2})
+		}
+		if len(circuits) == 1 && len(circuits[0]) == nb_jb {
+			res1,res2 = b1,b2
+			break
+		}
+	}
+	
+	return res1,res2
+}
+
+func merge_circuits(idx_cir, box int, circuits* [][]int) {
+	idx_cir_tomerge := -1
+	for i := range *circuits{
+		if slices.Contains((*circuits)[i],box){
+			idx_cir_tomerge = i
+		}
+	}
+	if idx_cir_tomerge >= 0 {
+		(*circuits)[idx_cir] = append((*circuits)[idx_cir], (*circuits)[idx_cir_tomerge]...)
+		(*circuits)[idx_cir_tomerge] = (*circuits)[len(*circuits)-1]
+		(*circuits) = (*circuits)[:len(*circuits)-1]
+	} else {
+		(*circuits)[idx_cir] = append((*circuits)[idx_cir], box)
+	}
+}
+
+type j_box_distance struct {
+	b1,b2 int
+	dis float64
+}
+
+type sj_box_distances []j_box_distance
+
+func (a sj_box_distances) Len() int { return len(a)}
+func (a sj_box_distances) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
+func (a sj_box_distances) Less(i, j int) bool { return a[i].dis < a[j].dis }
+
+
+func calculate_distances(points [][]int64) sj_box_distances {
+	var res sj_box_distances
+	for i := range(points) {
+		for j := i+1; j < len(points); j++{
+			b1,b2 := i,j
+			dis := euclidiean_distance(points[i],points[j]) 
+			res = append(res, j_box_distance{b1,b2,dis})
+		}
+	}
+	sort.Sort(res)
+	return res
+}
+
+func euclidiean_distance(p1, p2 []int64) float64 {	
+	dx,dy,dz := math.Pow(float64(p1[0] - p2[0]), 2.0), math.Pow(float64(p1[1] - p2[1]), 2.0), math.Pow(float64(p1[2] - p2[2]), 2.0)
+	return math.Sqrt(dx + dy + dz)
+}

README.md

@@ -27,7 +27,7 @@ Each day's folder is named after the day number (`1` to `12`). Inside each folde
 | 5   | ✅     | ✅     |
 | 6   | ✅     | ✅     |
 | 7   | ✅     | ✅     |
-| 8   | ⬜     | ⬜     |
+| 8   | ✅     | ✅     |
 | 9   | ⬜     | ⬜     |
 | 10  | ⬜     | ⬜     |
 | 11  | ⬜     | ⬜     |