2018 day 10 done

2018-12-10 08:37:20 -06:00
parent 93676db103
commit e1d46e7b90
4 changed files with 555 additions and 0 deletions
--- a/2018/day10/day10.go
+++ b/2018/day10/day10.go
@@ -0,0 +1,173 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+const (
+	MaxInt      = int(^uint(0) >> 1)
+	MinInt      = -MaxInt - 1
+	ClearScreen = "\033[H\033[2J"
+)
+
+var sky *Sky
+
+func main() {
+	inp := StdinToStringSlice()
+	buildSky(inp)
+	part1()
+}
+
+func buildSky(inp []string) {
+	sky = &Sky{
+		minPos: Pos{x: MaxInt, y: MaxInt},
+		maxPos: Pos{x: MinInt, y: MinInt},
+	}
+	for _, v := range inp {
+		sky.addStar(v)
+	}
+}
+
+func part1() {
+	for i := 1; i < 100000; i++ {
+		sky.tick()
+		if sky.maxPos.y-sky.minPos.y <= 10 {
+			sky.printSky()
+			fmt.Println("Seconds:", i)
+			break
+		}
+	}
+}
+
+type Sky struct {
+	stars          []*Star
+	minPos, maxPos Pos
+}
+
+func (s *Sky) tick() {
+	s.setMinPosX(MaxInt)
+	s.setMinPosY(MaxInt)
+	s.setMaxPosX(MinInt)
+	s.setMaxPosY(MinInt)
+	for _, v := range s.stars {
+		v.tick()
+		s.considerStar(v)
+	}
+}
+
+func (s *Sky) considerStar(v *Star) {
+	if v.position.x < s.minPos.x {
+		s.setMinPosX(v.position.x)
+	}
+	if v.position.y < s.minPos.y {
+		s.setMinPosY(v.position.y)
+	}
+	if v.position.x > s.maxPos.x {
+		s.setMaxPosX(v.position.x)
+	}
+	if v.position.y > s.maxPos.y {
+		s.setMaxPosY(v.position.y)
+	}
+}
+
+func (s *Sky) starAt(p *Pos) bool {
+	for _, v := range s.stars {
+		if p.equals(v.position) {
+			return true
+		}
+	}
+	return false
+}
+
+func (s *Sky) printSky() {
+	for i := s.minPos.y; i <= s.maxPos.y; i++ {
+		for j := s.minPos.x; j <= s.maxPos.x; j++ {
+			if s.starAt(&Pos{x: j, y: i}) {
+				fmt.Print("*")
+			} else {
+				fmt.Print(" ")
+			}
+		}
+		fmt.Println("")
+	}
+}
+
+func (s *Sky) addStar(inp string) {
+	v := NewStar(inp)
+	s.stars = append(s.stars, v)
+	s.considerStar(v)
+}
+
+func (s *Sky) setMinPosX(x int) {
+	s.minPos.x = x
+}
+func (s *Sky) setMinPosY(y int) {
+	s.minPos.y = y
+}
+func (s *Sky) setMaxPosX(x int) {
+	s.maxPos.x = x
+}
+func (s *Sky) setMaxPosY(y int) {
+	s.maxPos.y = y
+}
+
+type Star struct {
+	position *Pos
+	velocity *Pos
+}
+
+func NewStar(inp string) *Star {
+	inp = inp[10:]
+	pts := strings.Split(inp, ">")
+	posStr := pts[0]
+	velStr := pts[1][11:len(pts[1])]
+	return &Star{
+		position: NewPos(posStr),
+		velocity: NewPos(velStr),
+	}
+}
+
+func (s *Star) tick() {
+	s.position.x += s.velocity.x
+	s.position.y += s.velocity.y
+}
+
+type Pos struct {
+	x, y int
+}
+
+func NewPos(inp string) *Pos {
+	pts := strings.Split(inp, ", ")
+	return &Pos{
+		x: Atoi(strings.TrimSpace(pts[0])),
+		y: Atoi(strings.TrimSpace(pts[1])),
+	}
+}
+
+func (p *Pos) equals(o *Pos) bool {
+	return p.x == o.x && p.y == o.y
+}
+
+func StdinToStringSlice() []string {
+	var input []string
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		input = append(input, scanner.Text())
+	}
+	return input
+}
+
+func Atoi(i string) int {
+	var ret int
+	var err error
+	if ret, err = strconv.Atoi(i); err != nil {
+		fmt.Println(err.Error())
+		log.Fatal("Invalid Atoi" + i)
+	}
+	return ret
+}