aoc2024/day-05/internal/one/solve.go

package one

import (
	"bytes"
	"slices"

	"github.com/onyx-and-iris/aoc2024/day-05/internal/util"
)

func Solve(buf []byte) (int, error) {
	r := bytes.NewReader(buf)
	data, err := util.ParseLines(r)
	if err != nil {
		return 0, err
	}

	var sum int

	for i, products := range data[1] {
		inOrder := true
		for _, product := range products {
			for _, rules := range data[0] {
				if !slices.Contains(rules, product) {
					continue
				}

				indx1, indx2 := slices.Index(products, rules[0]), slices.Index(products, rules[1])
				if indx1 != -1 && indx2 != -1 && indx2 < indx1 {
					inOrder = false
					break
				}
			}
			if !inOrder {
				break
			}
		}
		if inOrder {
			sum += data[1][i][len(data[1][i])/2]
		}
	}

	return sum, nil
}