Restyled README and file structure

Signed-off-by: Ettore Dreucci <ettore.dreucci@gmail.com>

2019/day_06/day_06.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+)
+
+func readValues(fileName string) map[string]string {
+	file, err := os.Open(fileName)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer file.Close()
+
+	orbits := make(map[string]string)
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		value := scanner.Text()
+		planets := strings.Split(value, ")")
+		orbits[planets[1]] = planets[0]
+	}
+
+	return orbits
+}
+
+func getOrbitsNum(planet string, orbits map[string]string) int {
+	orbitsNum := 0
+	key := planet
+	orbit, hasOrbit := orbits[key]
+
+	for hasOrbit {
+		orbitsNum++
+		key = orbit
+		orbit, hasOrbit = orbits[key]
+	}
+
+	return orbitsNum
+}
+
+func getMinOrbitalTransfers(from string, to string, orbits map[string]string) int {
+	path := make(map[string]int)
+	orbit, hasOrbit := orbits[from]
+	distance := 0
+
+	for hasOrbit {
+		distance++
+		path[orbit] = distance
+		orbit, hasOrbit = orbits[orbit]
+	}
+
+	orbit, hasOrbit = orbits[to]
+	distance = 0
+
+	for hasOrbit {
+		dist, isInPath := path[orbit]
+		if isInPath {
+			distance += dist
+			return distance - 1
+		}
+		distance++
+		orbit, hasOrbit = orbits[orbit]
+	}
+	return -1
+}
+
+func main() {
+	orbits := readValues("./input")
+
+	orbitsNum := 0
+	for planet := range orbits {
+		orbitsNum += getOrbitsNum(planet, orbits)
+	}
+	fmt.Printf("Part 1: %d\n", orbitsNum)
+
+	minDist := getMinOrbitalTransfers("YOU", "SAN", orbits)
+	fmt.Printf("Part 2: %d\n", minDist)
+}