2020 Day 17 Complete

2020/day17/input

@@ -0,0 +1,8 @@
+....###.
+#...####
+##.#.###
+..#.#...
+##.#.#.#
+#.######
+..#..#.#
+######.#

2020/day17/main.go

@@ -0,0 +1,115 @@
+package main
+
+import (
+	"fmt"
+
+	h "git.bullercodeworks.com/brian/adventofcode/helpers"
+)
+
+func main() {
+	fmt.Println("# Day 17")
+	fmt.Println()
+	inp := h.StdinToStringSlice()
+	//field := h.StringSliceToCoord3dByteMap(inp)
+	//part1old(field)
+	fmt.Println("## Part 1:\nAnswer:", run(inp, 3))
+	fmt.Println("## Part 2:\nAnswer:", run(inp, 4))
+}
+
+func run(inp []string, dim int) int {
+	cs := NewCubeMapFromLines(inp)
+	for i := 0; i < 6; i++ {
+		next := NewCubeMap()
+		wrk := cs.Copy()
+		for _, c := range cs.ToSlice() {
+			wrk.AddMany(c.Neighbors(dim))
+		}
+		for _, c := range wrk.ToSlice() {
+			active := cs.Contains(c)
+			cnt := 0
+			for _, n := range c.Neighbors(dim) {
+				if cs.Contains(n) {
+					cnt++
+				}
+			}
+			if cnt == 3 || (active && cnt == 2) {
+				next.Add(c)
+			}
+		}
+		cs = next
+	}
+	return cs.Size()
+}
+
+type Cube struct {
+	X, Y, Z, W int
+}
+
+func (c Cube) Neighbors(d int) []Cube {
+	ret := []Cube{}
+	for dx := -1; dx <= 1; dx++ {
+		for dy := -1; dy <= 1; dy++ {
+			for dz := -1; dz <= 1; dz++ {
+				for dw := -(d - 3); dw <= d-3; dw++ {
+					if dx == 0 && dy == 0 && dz == 0 && dw == 0 {
+						continue
+					}
+					ret = append(ret, Cube{c.X + dx, c.Y + dy, c.Z + dz, c.W + dw})
+				}
+			}
+		}
+	}
+	return ret
+}
+
+type CubeMap struct {
+	field map[Cube]bool
+}
+
+func NewCubeMap() *CubeMap {
+	return &CubeMap{map[Cube]bool{}}
+}
+func NewCubeMapFromLines(inp []string) *CubeMap {
+	cs := NewCubeMap()
+	for y, line := range inp {
+		for x, b := range line {
+			if b == '#' {
+				cs.Add(Cube{x, y, 0, 0})
+			}
+		}
+	}
+	return cs
+}
+
+func (cs *CubeMap) Add(c Cube) {
+	cs.field[c] = true
+}
+func (cs *CubeMap) AddMany(cubes []Cube) {
+	for _, c := range cubes {
+		cs.Add(c)
+	}
+}
+func (cs *CubeMap) Remove(c Cube) {
+	delete(cs.field, c)
+}
+func (cs *CubeMap) Contains(c Cube) bool {
+	_, ok := cs.field[c]
+	return ok
+}
+func (cs *CubeMap) Copy() *CubeMap {
+	field := map[Cube]bool{}
+	for c := range cs.field {
+		field[c] = true
+	}
+	return &CubeMap{field}
+}
+func (cs *CubeMap) Size() int {
+	return len(cs.field)
+}
+func (cs *CubeMap) ToSlice() []Cube {
+	ret := []Cube{}
+	for c := range cs.field {
+		ret = append(ret, Cube{c.X, c.Y, c.Z, c.W})
+	}
+	return ret
+}

2020/day17/testinput

@@ -0,0 +1,3 @@
+.#.
+..#
+###