2019 Day 10 Complete

2019/day10/input

@@ -0,0 +1,41 @@
+.#....#.###.........#..##.###.#.....##...
+...........##.......#.#...#...#..#....#..
+...#....##..##.......#..........###..#...
+....#....####......#..#.#........#.......
+...............##..#....#...##..#...#..#.
+..#....#....#..#.....#.#......#..#...#...
+.....#.#....#.#...##.........#...#.......
+#...##.#.#...#.......#....#........#.....
+....##........#....#..........#.......#..
+..##..........##.....#....#.........#....
+...#..##......#..#.#.#...#...............
+..#.##.........#...#.#.....#........#....
+#.#.#.#......#.#...##...#.........##....#
+.#....#..#.....#.#......##.##...#.......#
+..#..##.....#..#.........#...##.....#..#.
+##.#...#.#.#.#.#.#.........#..#...#.##...
+.#.....#......##..#.#..#....#....#####...
+........#...##...#.....#.......#....#.#.#
+#......#..#..#.#.#....##..#......###.....
+............#..#.#.#....#.....##..#......
+...#.#.....#..#.......#..#.#............#
+.#.#.....#..##.....#..#..............#...
+.#.#....##.....#......##..#...#......#...
+.......#..........#.###....#.#...##.#....
+.....##.#..#.....#.#.#......#...##..#.#..
+.#....#...#.#.#.......##.#.........#.#...
+##.........#............#.#......#....#..
+.#......#.............#.#......#.........
+.......#...##........#...##......#....#..
+#..#.....#.#...##.#.#......##...#.#..#...
+#....##...#.#........#..........##.......
+..#.#.....#.....###.#..#.........#......#
+......##.#...#.#..#..#.##..............#.
+.......##.#..#.#.............#..#.#......
+...#....##.##..#..#..#.....#...##.#......
+#....#..#.#....#...###...#.#.......#.....
+.#..#...#......##.#..#..#........#....#..
+..#.##.#...#......###.....#.#........##..
+#.##.###.........#...##.....#..#....#.#..
+..........#...#..##..#..##....#.........#
+..#..#....###..........##..#...#...#..#..

2019/day10/main.go

@@ -0,0 +1,90 @@
+package main
+
+import (
+	"fmt"
+	"sort"
+
+	helpers "git.bullercodeworks.com/brian/adventofcode/helpers"
+)
+
+const MaxInt = int(^uint(0) >> 1)
+
+var field []helpers.Coordinate
+
+func main() {
+	inp := helpers.StdinToStringSlice()
+	initField(inp)
+	solve()
+}
+
+func initField(inp []string) {
+	for y, yb := range inp {
+		for x, xb := range yb {
+			if xb != '#' {
+				continue
+			}
+			field = append(field, helpers.Coordinate{X: x, Y: y})
+		}
+	}
+}
+
+func solve() {
+	// Figure out the best place to put the station
+	var bestCount int
+	var best helpers.Coordinate
+	var bestAngles map[float64][]helpers.Coordinate
+	for _, wrk := range field {
+		angles := make(map[float64][]helpers.Coordinate)
+		var count int
+		for _, tgt := range field {
+			if wrk == tgt {
+				continue
+			}
+			a := wrk.Angle(tgt)
+			if _, ok := angles[a]; !ok {
+				count++
+			}
+			angles[a] = append(angles[a], tgt)
+		}
+		if count > bestCount {
+			bestCount = count
+			best = wrk
+			bestAngles = angles
+		}
+	}
+	fmt.Println("Part 1:", best, bestCount)
+
+	var angleSlice []float64
+	for k := range bestAngles {
+		angleSlice = append(angleSlice, k)
+	}
+	sort.Float64s(angleSlice)
+	// Now start vaporizing
+	var hitCount int
+	var c200 helpers.Coordinate
+	for k := range bestAngles {
+		sort.Slice(bestAngles[k], func(i, j int) bool {
+			return bestAngles[k][i].Distance(best) < bestAngles[k][j].Distance(best)
+		})
+	}
+
+	for len(bestAngles) > 0 {
+		for _, v := range angleSlice {
+			if roids, ok := bestAngles[v]; ok {
+				// Destroy the first asteroid in the list
+				hitCount++
+				if hitCount == 200 {
+					c200 = roids[0]
+					res := (c200.X*100 + c200.Y)
+					fmt.Println("Part 2:", c200, res)
+					return
+				}
+				if len(roids) > 1 {
+					bestAngles[v] = roids[1:]
+				} else {
+					delete(bestAngles, v)
+				}
+			}
+		}
+	}
+}

2019/day10/testinput1

@@ -0,0 +1,5 @@
+.#..#
+.....
+#####
+....#
+...##

2019/day10/testinput2

@@ -0,0 +1,10 @@
+......#.#.
+#..#.#....
+..#######.
+.#.#.###..
+.#..#.....
+..#....#.#
+#..#....#.
+.##.#..###
+##...#..#.
+.#....####

2019/day10/testinput3

@@ -0,0 +1,10 @@
+#.#...#.#.
+.###....#.
+.#....#...
+##.#.#.#.#
+....#.#.#.
+.##..###.#
+..#...##..
+..##....##
+......#...
+.####.###.

2019/day10/testinput4

@@ -0,0 +1,10 @@
+.#..#..###
+####.###.#
+....###.#.
+..###.##.#
+##.##.#.#.
+....###..#
+..#.#..#.#
+#..#.#.###
+.##...##.#
+.....#.#..

2019/day10/testinput5

@@ -0,0 +1,20 @@
+.#..##.###...#######
+##.############..##.
+.#.######.########.#
+.###.#######.####.#.
+#####.##.#.##.###.##
+..#####..#.#########
+####################
+#.####....###.#.#.##
+##.#################
+#####.##.###..####..
+..######..##.#######
+####.##.####...##..#
+.#####..#.######.###
+##...#.##########...
+#.##########.#######
+.####.#.###.###.#.##
+....##.##.###..#####
+.#.#.###########.###
+#.#.#.#####.####.###
+###.##.####.##.#..##

helpers/coordinate.go

@@ -0,0 +1,37 @@
+package aoc
+
+import (
+	"fmt"
+	"math"
+	"strings"
+)
+
+type Coordinate struct {
+	X, Y int
+}
+
+func CoordinateFromString(str string) *Coordinate {
+	c := Coordinate{}
+	r := strings.NewReader(str)
+	_, err := fmt.Fscanf(r, "[%d, %d]", c.X, c.Y)
+	if err != nil {
+		panic(err)
+	}
+	return &c
+}
+
+func (c Coordinate) Angle(t Coordinate) float64 {
+	ret := math.Atan2(float64(t.X-c.X), float64(c.Y-t.Y)) * 180 / math.Pi
+	if ret < 0 {
+		ret = ret + 360
+	}
+	return ret
+}
+
+func (c Coordinate) String() string {
+	return fmt.Sprintf("[%d, %d]", c.X, c.Y)
+}
+
+func (c Coordinate) Distance(t Coordinate) int {
+	return AbsInt(c.X-t.X) + AbsInt(c.Y-t.Y)
+}

helpers/helpers.go

@@ -27,6 +27,13 @@ const (
 	MIN_INT = -MAX_INT - 1
 )
 
+func AbsInt(i int) int {
+	if i < 0 {
+		return i * -1
+	}
+	return i
+}
+
 func ArgIsSet(a string) bool {
 	for i := range os.Args {
 		if os.Args[i] == a || strings.HasPrefix(os.Args[i], a+"=") {