package main

import (
	"io"
	"log"
	"os"
	"strconv"
	"strings"
)

func main() {
	if err := myMain(); err != nil {
		log.Println(err)
	}
}

func myMain() error {
	// parse input.txt
	crabs, err := parseInput("input.txt")
	if err != nil {
		return err
	}

	log.Println(solveFirst(crabs))
	log.Println(solveSecond(crabs))

	return nil
}

func solveFirst(crabs []int) int {
	var least int
	for i := 0; ; i++ {
		var fuel int
		for _, crab := range crabs {
			fuel += abs(crab - i)
		}
		if i == 0 {
			least = fuel
			continue
		}
		if fuel < least {
			least = fuel
		} else {
			break
		}
	}
	return least
}

func solveSecond(crabs []int) int {
	var least int
	for i := 0; ; i++ {
		var fuel int
		for _, crab := range crabs {
			diff := abs(crab - i)
			if diff == 0 {
				continue
			}
			fuel += (diff * (diff + 1)) / 2 // Gauss would be proud :-)
		}
		if i == 0 {
			least = fuel
			continue
		}
		if fuel < least {
			least = fuel
		} else {
			break
		}
	}
	return least
}

func abs(a int) int {
	if a < 0 {
		return -a
	}
	return a
}

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
}