2020 Day 11 Complete

2020/day11/main.go

@@ -0,0 +1,263 @@
+package main
+
+import (
+	"fmt"
+
+	h "git.bullercodeworks.com/brian/adventofcode/helpers"
+)
+
+const (
+	EMPTY = 'L'
+	FULL  = '#'
+	FLOOR = '.'
+
+	N = iota
+	NE
+	E
+	SE
+	S
+	SW
+	W
+	NW
+)
+
+func main() {
+	fmt.Println("# Day 11")
+	inp := h.StdinToStringSlice()
+	pt := h.GetArgNumber(1)
+	if pt == "1" {
+		part1(inp)
+	} else {
+		part2(inp)
+	}
+}
+
+func part1(inp []string) {
+	fmt.Println("## Part 1")
+	w := BuildWaitingRoom(inp)
+	var last string
+	for w.String() != last {
+		last = w.String()
+		w.Tick()
+	}
+	fmt.Println(w)
+	fmt.Printf("At stabilization there are %d occupied seats\n", w.OccupiedSeats())
+}
+
+func part2(inp []string) {
+	fmt.Println("## Part 2")
+	w := BuildWaitingRoom(inp)
+	var last string
+	for w.String() != last {
+		last = w.String()
+		w.VisibleTick()
+	}
+	fmt.Println(w)
+	fmt.Printf("At stabilization there are %d occupied seats\n", w.OccupiedSeats())
+}
+
+type WaitingRoom struct {
+	Layout    map[h.Coordinate]byte
+	NorthMost int
+	SouthMost int
+	EastMost  int
+	WestMost  int
+}
+
+func BuildWaitingRoom(inp []string) *WaitingRoom {
+	ret := WaitingRoom{
+		Layout:    make(map[h.Coordinate]byte),
+		NorthMost: h.MAX_INT,
+		SouthMost: h.MIN_INT,
+		EastMost:  h.MIN_INT,
+		WestMost:  h.MAX_INT,
+	}
+
+	for y := range inp {
+		for x := range inp[y] {
+			ret.Layout[h.Coordinate{X: x, Y: y}] = inp[y][x]
+			if x < ret.WestMost {
+				ret.WestMost = x
+			}
+			if x > ret.EastMost {
+				ret.EastMost = x
+			}
+		}
+		if y < ret.NorthMost {
+			ret.NorthMost = y
+		}
+		if y > ret.SouthMost {
+			ret.SouthMost = y
+		}
+	}
+	return &ret
+}
+
+func (w *WaitingRoom) OccupiedSeats() int {
+	var ret int
+	for k := range w.Layout {
+		if !w.CoordEmpty(k) {
+			ret++
+		}
+	}
+	return ret
+}
+
+func (w *WaitingRoom) CoordEmpty(c h.Coordinate) bool {
+	return w.Layout[c] != FULL
+}
+
+func (w *WaitingRoom) ShouldFill(c h.Coordinate) bool {
+	if w.Layout[c] == FULL || w.Layout[c] == FLOOR {
+		return false
+	}
+	return w.CoordEmpty(c.North()) && w.CoordEmpty(c.NE()) && w.CoordEmpty(c.East()) && w.CoordEmpty(c.SE()) && w.CoordEmpty(c.South()) && w.CoordEmpty(c.SW()) && w.CoordEmpty(c.West()) && w.CoordEmpty(c.NW())
+}
+
+func (w *WaitingRoom) ShouldEmpty(c h.Coordinate) bool {
+	if w.Layout[c] == EMPTY || w.Layout[c] == FLOOR {
+		return false
+	}
+	var fullSeats int
+	for _, v := range []h.Coordinate{c.North(), c.NE(), c.East(), c.SE(), c.South(), c.SW(), c.West(), c.NW()} {
+		if !w.CoordEmpty(v) {
+			fullSeats++
+			if fullSeats >= 4 {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+func (w *WaitingRoom) Tick() {
+	wrk := make(map[h.Coordinate]byte)
+	for k := range w.Layout {
+		wrk[k] = w.Layout[k]
+		switch w.Layout[k] {
+		case EMPTY:
+			if w.ShouldFill(k) {
+				wrk[k] = FULL
+			}
+
+		case FULL:
+			if w.ShouldEmpty(k) {
+				wrk[k] = EMPTY
+			}
+		}
+	}
+	for k := range wrk {
+		w.Layout[k] = wrk[k]
+	}
+}
+
+func (w *WaitingRoom) IsFloor(c h.Coordinate) bool {
+	return w.Layout[c] == FLOOR
+}
+
+func (w *WaitingRoom) GetCoordInDir(c h.Coordinate, dir int) h.Coordinate {
+	switch dir {
+	case N:
+		return c.North()
+	case NE:
+		return c.NE()
+	case E:
+		return c.East()
+	case SE:
+		return c.SE()
+	case S:
+		return c.South()
+	case SW:
+		return c.SW()
+	case W:
+		return c.West()
+	case NW:
+		return c.NW()
+	}
+	return c
+}
+
+func (w *WaitingRoom) DirectionEmpty(c h.Coordinate, dir int) bool {
+	c = w.GetCoordInDir(c, dir)
+	for w.IsFloor(c) {
+		c = w.GetCoordInDir(c, dir)
+	}
+	return w.CoordEmpty(c)
+}
+
+func (w *WaitingRoom) VisibleShouldFill(c h.Coordinate) bool {
+	if w.Layout[c] == FULL || w.Layout[c] == FLOOR {
+		return false
+	}
+	return w.DirectionEmpty(c, N) && w.DirectionEmpty(c, NE) && w.DirectionEmpty(c, E) && w.DirectionEmpty(c, SE) && w.DirectionEmpty(c, S) && w.DirectionEmpty(c, SW) && w.DirectionEmpty(c, W) && w.DirectionEmpty(c, NW)
+}
+
+func (w *WaitingRoom) VisibleShouldEmpty(c h.Coordinate) bool {
+	if w.Layout[c] == EMPTY || w.Layout[c] == FLOOR {
+		return false
+	}
+	var fullSeats int
+	for _, v := range []int{N, NE, E, SE, S, SW, W, NW} {
+		if !w.DirectionEmpty(c, v) {
+			fullSeats++
+			if fullSeats >= 5 {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+func (w *WaitingRoom) VisibleTick() {
+	wrk := make(map[h.Coordinate]byte)
+	for k := range w.Layout {
+		wrk[k] = w.Layout[k]
+		switch w.Layout[k] {
+		case EMPTY:
+			if w.VisibleShouldFill(k) {
+				wrk[k] = FULL
+			}
+
+		case FULL:
+			if w.VisibleShouldEmpty(k) {
+				wrk[k] = EMPTY
+			}
+		}
+	}
+	for k := range wrk {
+		w.Layout[k] = wrk[k]
+	}
+}
+
+func (w WaitingRoom) String() string {
+	var ret string
+	for y := w.NorthMost; y <= w.SouthMost; y++ {
+		for x := w.WestMost; x <= w.EastMost; x++ {
+			ret = ret + string(w.Layout[h.Coordinate{X: x, Y: y}])
+		}
+		ret = ret + "\n"
+	}
+	return ret
+}
+
+func DirToStr(dir int) string {
+	switch dir {
+	case N:
+		return "N"
+	case NE:
+		return "NE"
+	case E:
+		return "E"
+	case SE:
+		return "SE"
+	case S:
+		return "S"
+	case SW:
+		return "SW"
+	case W:
+		return "W"
+	case NW:
+		return "NW"
+	}
+	return "-"
+}