2019/day1/main.go

package main

import (
	"bufio"
	"log"
	"os"
	"strconv"
)

func main() {
	file, err := os.Open("input.txt")
	if err != nil {
		log.Fatal(err)
	}
	defer file.Close()

	completeFuel := 0
	recursiveFuel := 0

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		txt := scanner.Text()
		convert, err := strconv.ParseFloat(txt, 64)

		if err != nil {
			log.Fatal(err)
		}

		completeFuel += CalcRequiredFuel(convert)
		recursiveFuel += CalcFuelRecusive(convert)
	}

	if err := scanner.Err(); err != nil {
		log.Fatal(err)
	}

	log.Println("Part1: " + strconv.Itoa(completeFuel))
	log.Println("Part2: " + strconv.Itoa(recursiveFuel))
}

func CalcFuelRecusive(mass float64) int {
	sum := 0
	for mass > 0 {
		fuel := CalcRequiredFuel(mass)

		if fuel > 0 {
			sum += fuel
		}
		mass = float64(fuel)
	}
	return sum
}

func CalcRequiredFuel(mass float64) int {
	fuel := mass / 3
	return int(fuel) - 2
}