adventofcode

day2.go (1498B)

package main
import (
	"fmt"
	"io/ioutil"
	"math"
	"os"
	"strconv"
	"strings"
)
func line_positions(line string) (positions [][2]int) {
	position := [2]int{0, 0} // (x,y)
	for _, move := range strings.Split(line, ",") {
		direction := strings.Split(move, "")[0]
		amount, err := strconv.Atoi(move[1:])
		if err != nil {
			fmt.Println(err)
		}
		for i := 0; i < amount; i++ {
			switch direction {
			case "U":
				position[0]++
			case "D":
				position[0]--
			case "L":
				position[1]++
			case "R":
				position[1]--
			}
			positions = append(positions, position)
		}
	}
	return
}
func main() {
	if len(os.Args) != 2 {
		fmt.Printf("Usage: %s [input file]\n", os.Args[0])
		os.Exit(1)
	}
	inputPath := os.Args[1]
	content, err := ioutil.ReadFile(inputPath)
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}
	fileString := string(content)
	lines := strings.Split(fileString, "\n")
	line1 := line_positions(lines[0])
	line2 := line_positions(lines[1])
	var intercepts [][2]int
	for _, pos1 := range line1 {
		for _, pos2 := range line2 {
			if pos1 == pos2 {
				intercepts = append(intercepts, pos1)
			}
		}
	}
	fmt.Printf("%3d\n", intercepts)
	minDistance := float64(0)
	for _, intercept := range intercepts {
		var distance float64
		distance += math.Abs(float64(intercept[0]))
		distance += math.Abs(float64(intercept[1]))
		
		if minDistance == 0 {
			minDistance = distance
		} else {
			minDistance = math.Min(minDistance, distance)
		}
	}
	fmt.Println(minDistance)
}