aoc_2024/2025/seven/seven.go

package main

import (
	"bufio"
	"fmt"
	"os"
	"strings"
)

func check(err error) {
	if err != nil {
		panic(err)
	}
}

type beams struct {
	list map[int]int
}

func newBeams() beams {
	var b beams
	b.list = make(map[int]int)
	return b
}

func (b *beams) add(pos int) {
	b.list[pos]++
}

func (b *beams) del(pos int) {
	delete(b.list, pos)
}

func main() {

	file, err := os.Open("seven.txt")
	check(err)
	defer file.Close()

	scanner := bufio.NewScanner(file)
	scanner.Scan()

	text := scanner.Text()

	start := strings.IndexRune(text, 'S')
	beamSet := make(map[int]int)
	beamSet[start] = 1

	for scanner.Scan() {
		text := scanner.Text()
		for beam, nways := range beamSet {
			if text[beam] == '^' {
				beamSet[beam-1] += nways
				beamSet[beam+1] += nways
				delete(beamSet, beam)
			}
		}
	}

	timelines := 0
	for _, nways := range beamSet {
		timelines += nways
	}

	fmt.Printf("N splits: %d\n", timelines)
}