2025, day 10, part1

Author: lucianoq

2025/10/Makefile

@@ -0,0 +1,20 @@
+input:
+	http "https://adventofcode.com/2025/day/10/input" "Cookie:session=${AOC_SESSION};" >input
+
+main1:
+	go build -o main1 main1.go common.go
+
+main2:
+	go build -o main2 main2.go common.go
+
+.PHONY: run1 run2 clean
+
+run1: main1 input
+	./main1 <input
+
+run2: main2 input
+	./main2 <input
+
+clean:
+	rm -f main1 main2 input
+

2025/10/common.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"bufio"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type Machine struct {
+	Indicator  uint16
+	Buttons    []uint16
+	ButtonsInt [][]int
+	Joltage    []int
+}
+
+func parseInput() []Machine {
+	var list []Machine
+
+	for scanner := bufio.NewScanner(os.Stdin); scanner.Scan(); {
+		tokens := strings.Split(scanner.Text(), " ")
+
+		indicatorS := strings.Trim(tokens[0], "[]")
+		var indicator uint16
+		for i, c := range indicatorS {
+			if c == '#' {
+				indicator |= 1 << uint16(len(indicatorS)-i-1)
+			}
+		}
+
+		var buttons []uint16
+		var buttonsInt [][]int
+		for i := 1; i < len(tokens)-1; i++ {
+			buttonS := strings.Split(strings.Trim(tokens[i], "()"), ",")
+			buttonInt := make([]int, len(buttonS))
+			var button uint16
+			for j, b := range buttonS {
+				n, _ := strconv.Atoi(b)
+				buttonInt[j] = n
+				button |= 1 << uint16(len(indicatorS)-n-1)
+			}
+			buttons = append(buttons, button)
+			buttonsInt = append(buttonsInt, buttonInt)
+		}
+
+		joltageS := strings.Split(strings.Trim(tokens[len(tokens)-1], "{}"), ",")
+		joltage := make([]int, len(joltageS))
+		for i := range joltageS {
+			joltage[i], _ = strconv.Atoi(joltageS[i])
+		}
+		list = append(list, Machine{indicator, buttons, buttonsInt, joltage})
+	}
+	return list
+}

2025/10/main1.go

@@ -0,0 +1,40 @@
+package main
+
+import "fmt"
+
+func main() {
+	list := parseInput()
+	sum := 0
+	for _, m := range list {
+		sum += m.BFS()
+	}
+	fmt.Println(sum)
+}
+
+func (m Machine) BFS() int {
+	if m.Indicator == 0 {
+		return 0
+	}
+
+	dist := map[uint16]int{0: 0}
+	queue := []uint16{0}
+	for len(queue) > 0 {
+		var curr uint16
+		curr, queue = queue[0], queue[1:]
+		currDist := dist[curr]
+
+		for _, b := range m.Buttons {
+			nextVal := curr ^ b
+
+			if nextVal == m.Indicator {
+				return currDist + 1
+			}
+
+			if _, ok := dist[nextVal]; !ok {
+				dist[nextVal] = currDist + 1
+				queue = append(queue, nextVal)
+			}
+		}
+	}
+	return -1
+}