package main
import (
	"io"
	"log"
	"os"
	"strconv"
	"strings"
)
const (
	AGES = 9
)
func main() {
	if err := myMain(); err != nil {
		log.Println(err)
	}
}
func myMain() error {
	// parse input.txt
	lanterns, err := parseInput("input.txt")
	if err != nil {
		return err
	}
	log.Println(solveFirst(lanterns, 80))
	log.Println(solveFirst(lanterns, 256))
	return nil
}
func solveFirst(lf []int, days int) int {
	age := lanternage(lf)
	for i := 0; i < days; i++ {
		new := age[0]
		age[0] = age[1]
		age[1] = age[2]
		age[2] = age[3]
		age[3] = age[4]
		age[4] = age[5]
		age[5] = age[6]
		age[6] = age[7] + new
		age[7] = age[8]
		age[8] = new
	}
	return sum(age)
}
func sum(in [AGES]int) int {
	var sum int
	for _, item := range in {
		sum += item
	}
	return sum
}
func lanternage(lf []int) [AGES]int {
	var ret [AGES]int
	for _, fish := range lf {
		ret[fish] += 1
	}
	return ret
}
func parseInput(fileName string) ([]int, error) {
	var ret []int
	fd, err := os.Open(fileName)
	if err != nil {
		return ret, err
	}
	defer fd.Close()
	input, err := io.ReadAll(fd)
	if err != nil {
		return nil, err
	}
	instr := strings.Split(strings.TrimSuffix(string(input), "\n"), ",")
	for _, elem := range instr {
		tmp, err := strconv.Atoi(elem)
		if err != nil {
			return nil, err
		}
		ret = append(ret, tmp)
	}
	return ret, nil
}

4,1,4,1,3,3,1,4,3,3,2,1,1,3,5,1,3,5,2,5,1,5,5,1,3,2,5,3,1,3,4,2,3,2,3,3,2,1,5,4,1,1,1,2,1,4,4,4,2,1,2,1,5,1,5,1,2,1,4,4,5,3,3,4,1,4,4,2,1,4,4,3,5,2,5,4,1,5,1,1,1,4,5,3,4,3,4,2,2,2,2,4,5,3,5,2,4,2,3,4,1,4,4,1,4,5,3,4,2,2,2,4,3,3,3,3,4,2,1,2,5,5,3,2,3,5,5,5,4,4,5,5,4,3,4,1,5,1,3,4,4,1,3,1,3,1,1,2,4,5,3,1,2,4,3,3,5,4,4,5,4,1,3,1,1,4,4,4,4,3,4,3,1,4,5,1,2,4,3,5,1,1,2,1,1,5,4,2,1,5,4,5,2,4,4,1,5,2,2,5,3,3,2,3,1,5,5,5,4,3,1,1,5,1,4,5,2,1,3,1,2,4,4,1,1,2,5,3,1,5,2,4,5,1,2,3,1,2,2,1,2,2,1,4,1,3,4,2,1,1,5,4,1,5,4,4,3,1,3,3,1,1,3,3,4,2,3,4,2,3,1,4,1,5,3,1,1,5,3,2,3,5,1,3,1,1,3,5,1,5,1,1,3,1,1,1,1,3,3,1

3,4,3,1,2

module main
go 1.17