Solve 2019 - Day 1

Signed-off-by: Alexander Kurbatov <sir.alkurbatov@yandex.ru>

Author: alkurbatov

2019/1/main.go

@@ -0,0 +1,67 @@
+// --- Day 1: The Tyranny of the Rocket Equation ---
+// https://adventofcode.com/2019/day/1
+package main
+
+import (
+	"bufio"
+	"log"
+	"os"
+	"strconv"
+)
+
+func readInput(path string) ([]int, error) {
+	input, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer input.Close()
+
+	output := make([]int, 0)
+	scanner := bufio.NewScanner(input)
+
+	for scanner.Scan() {
+		value, err := strconv.Atoi(scanner.Text())
+		if err != nil {
+			return nil, err
+		}
+
+		output = append(output, value)
+	}
+
+	return output, scanner.Err()
+}
+
+func calcFuel(mass int) int {
+	return max(mass/3-2, 0)
+}
+
+func calcFuelWithAdditionalFuel(mass int) int {
+	result := 0
+
+	for mass > 0 {
+		fuel := calcFuel(mass)
+
+		mass = fuel
+		result += fuel
+	}
+
+	return result
+}
+
+func main() {
+	input, err := readInput("./2019/1/input.txt")
+	if err != nil {
+		log.Printf("Failed to read data from input.txt: %v", err)
+		return
+	}
+
+	var firstPartResult, secondPartResult int
+
+	for _, mass := range input {
+		firstPartResult += calcFuel(mass)
+		secondPartResult += calcFuelWithAdditionalFuel(mass)
+	}
+
+	log.Printf("Part 1 result: %d", firstPartResult)
+	log.Printf("Part 2 result: %d", secondPartResult)
+}