2019 Day 10 Complete

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)
+				}
+			}
+		}
+	}
+}