Day 22 Part 1

cmd/day22/day22.go

@@ -0,0 +1,252 @@
+package main
+
+import (
+	"fmt"
+	"github.com/Olegas/advent-of-code-2022/internal/util"
+	"strings"
+
+	"github.com/Olegas/goaocd"
+)
+
+type Me struct {
+	pos    goaocd.Pos
+	facing goaocd.Pos
+}
+
+type Move struct {
+	steps int
+	rot   string
+}
+
+/**
+  A B
+  C
+D E
+F
+           /+
+      A   / |
+  +-----+/  |
+E |  C  | B/+
+  |     | /
+  +-----+/
+     D
+*/
+
+type Transition struct {
+	face   string
+	facing goaocd.Pos
+}
+
+//R: (1, 0)
+//R: (0, 1), L: (0, -1)
+
+//L: (-1, 0)
+//R: (0, -1), L: (0, 1)
+
+//U (0, -1)
+//R: (1, 0), L: (-1, 0)
+
+//D (0, 1)
+//R: (1, 0), L: (-1, 0)
+
+func (m *Me) Rotate(dir string) {
+	if dir == "" {
+		return
+	}
+	f := m.facing
+	v := f.Y != 0
+	mul := 1
+	if !v && dir == "L" || v && dir == "R" {
+		mul = -1
+	}
+	m.facing = goaocd.Pos{X: f.Y * mul, Y: f.X * mul}
+	if util.AbsDiffInt(m.facing.X, m.facing.Y) != 1 {
+		panic("Broken facing")
+	}
+}
+
+var wrapAround = make(map[Me]goaocd.Pos)
+
+type Dimensions struct {
+	MinX, MaxX, MinY, MaxY int
+}
+
+func dimensions(world map[goaocd.Pos]string) Dimensions {
+	xCoords := []int{}
+	yCoords := []int{}
+	for c := range world {
+		xCoords = append(xCoords, c.X)
+		yCoords = append(yCoords, c.Y)
+	}
+	minX, maxX := util.MinMax(xCoords)
+	minY, maxY := util.MinMax(yCoords)
+
+	return Dimensions{MinX: minX, MaxX: maxX, MinY: minY, MaxY: maxY}
+}
+
+func display(world map[goaocd.Pos]string, me Me) {
+	dim := Dimensions{
+		MinX: me.pos.X - 10,
+		MaxX: me.pos.X + 10,
+		MinY: me.pos.Y - 10,
+		MaxY: me.pos.Y + 10,
+	}
+	padding := 2
+
+	for y := dim.MinY - padding; y <= dim.MaxY+padding; y++ {
+		for x := dim.MinX - padding; x <= dim.MaxX+padding; x++ {
+			k := goaocd.Pos{X: x, Y: y}
+			s, ok := world[k]
+
+			if !ok {
+				s = " "
+			}
+			if me.pos.Eq(k) {
+				_, s = facingToInt(me.facing)
+			}
+			fmt.Print(s)
+		}
+		fmt.Print("\n")
+	}
+
+	fmt.Scanln()
+}
+
+func sample() []string {
+	d := `....
+....
+....
+...#
+
+0R0R0R0R0L0L0L0L`
+	return strings.Split(d, "\n")
+}
+
+func findNextWrapPos(world map[goaocd.Pos]string, me Me) goaocd.Pos {
+	r, ok := wrapAround[me]
+	if ok {
+		return r
+	}
+	pos := me.pos
+	facing := me.facing
+	opposite := goaocd.Pos{X: -facing.X, Y: -facing.Y}
+	for {
+		n := pos.Mut(opposite)
+		t, ok := world[n]
+		if !ok || t == " " {
+			wrapAround[me] = pos
+			return pos
+		}
+		pos = n
+	}
+}
+
+func (m *Me) Move(world map[goaocd.Pos]string, steps int) {
+	for i := 0; i < steps; i++ {
+		n := m.pos.Mut(m.facing)
+		t, ok := world[n]
+		if !ok || t == " " {
+			// wrap around
+			n = findNextWrapPos(world, *m)
+			t, ok := world[n]
+			if !ok {
+				panic("Wraparound is void!!!")
+			}
+			if t == "#" {
+				// wall after warp around, stop
+				break
+			}
+		} else if t == "#" {
+			break
+		}
+		// step
+		m.pos = n
+		// display(world, *m)
+	}
+}
+
+func facingToInt(pos goaocd.Pos) (int, string) {
+	if pos.X == 1 && pos.Y == 0 {
+		return 0, ">"
+	} else if pos.X == 0 && pos.Y == 1 {
+		return 1, "v"
+	} else if pos.X == -1 && pos.Y == 0 {
+		return 2, "<"
+	} else if pos.X == 0 && pos.Y == -1 {
+		return 3, "^"
+	}
+	panic("Incorrect facing")
+}
+
+func partA(world map[goaocd.Pos]string, moves []Move, me Me) int {
+	done := goaocd.Duration("Part A")
+	defer done()
+
+	for _, m := range moves {
+		fmt.Printf("%d%s\n", m.steps, m.rot)
+		me.Move(world, m.steps)
+		me.Rotate(m.rot)
+		// display(world, me)
+	}
+	fi, _ := facingToInt(me.facing)
+	fmt.Printf("%d * 1000 + %d * 4 + %d", me.pos.Y+1, me.pos.X+1, fi)
+	return (me.pos.Y+1)*1000 + (me.pos.X+1)*4 + fi
+}
+
+func partB() int {
+	done := goaocd.Duration("Part B")
+	defer done()
+
+	return 0
+}
+
+func loadMap(lines []string) (map[goaocd.Pos]string, []Move, Me) {
+	ret := make(map[goaocd.Pos]string)
+	me := Me{}
+	moves := []Move{}
+	mapMode := true
+	meFound := false
+	for y, line := range lines {
+		if line == "" {
+			mapMode = false
+			continue
+		}
+		if mapMode {
+			for x, s := range line {
+				p := goaocd.Pos{X: x, Y: y}
+				if !meFound && string(s) == "." {
+					me.pos = p
+					me.facing = goaocd.Pos{X: 1, Y: 0}
+					meFound = true
+				}
+				ret[p] = string(s)
+			}
+		} else {
+			dAccu := ""
+			for _, s := range line {
+				if util.IsDigit(byte(s)) {
+					dAccu += string(s)
+				} else {
+					m := Move{steps: util.Atoi(dAccu), rot: string(s)}
+					moves = append(moves, m)
+					dAccu = ""
+				}
+			}
+			if dAccu != "" {
+				m := Move{steps: util.Atoi(dAccu), rot: ""}
+				moves = append(moves, m)
+			}
+		}
+
+	}
+	return ret, moves, me
+}
+
+func main() {
+	lines := sample()
+	lines = goaocd.Lines()
+	world, moves, me := loadMap(lines)
+
+	fmt.Printf("Part A: %d\n", partA(world, moves, me))
+	fmt.Printf("Part B: %d\n", partB())
+}