aoc-2022/day03/solution.go

package day03

type Solver struct {
	rucksacks []Rucksack

	groups []ElfSet
}

type Rucksack struct {
	compartment1, compartment2 []byte
}

type ElfSet struct {
	elfItems [3]map[byte]bool
}

func (s *Solver) ParseInput(input []string) {
	s.rucksacks = make([]Rucksack, len(input))

	for i, line := range input {
		s.rucksacks[i] = Rucksack{
			compartment1: []byte(line[:len(line)/2]),
			compartment2: []byte(line[len(line)/2:]),
		}
	}
	// fmt.Printf("%v\n", s.rucksacks)

	var elfSet ElfSet
	for i, line := range input {
		elfIndex := i % len(elfSet.elfItems)
		if elfIndex == 0 {
			elfSet = ElfSet{}
		}
		if elfSet.elfItems[elfIndex] == nil {
			elfSet.elfItems[elfIndex] = make(map[byte]bool, 0)
		}
		for _, b := range []byte(line) {
			elfSet.elfItems[elfIndex][b] = true
		}
		if i%3 == 2 {
			s.groups = append(s.groups, elfSet)
		}
	}
	// fmt.Printf("%+v\n", s.groups)
}

func (s *Solver) SolvePart1() any {
	var total int

	for _, r := range s.rucksacks {
		m := make(map[byte]bool, 0)

		for _, b := range r.compartment1 {
			m[b] = true
		}
		for _, b := range r.compartment2 {
			if _, ok := m[b]; ok {
				total += getValue(b)
				break
			}
		}
	}

	return total
}
func getValue(b byte) int {
	if b >= 'a' && b <= 'z' {
		return int(b - 'a' + 1)
	} else {
		return int(b - 'A' + 27)
	}
}

func (s *Solver) SolvePart2() any {
	var total int
	for _, g := range s.groups {
		for item := range g.elfItems[0] {
			if _, ok := g.elfItems[1][item]; !ok {
				continue
			}
			if _, ok := g.elfItems[2][item]; !ok {
				continue
			}
			total += getValue(item)
			// fmt.Println(string(item))
			break
		}
	}
	return total
}