2018 Complete!

2018/day25/constellation.go

@@ -0,0 +1,55 @@
+package main
+
+import "math"
+
+type Coordinate [4]int
+
+func (c Coordinate) Distance(b Coordinate) int {
+	sum := 0
+	for i := 0; i < 4; i++ {
+		sum += abs(c[i] - b[i])
+	}
+	return sum
+}
+
+type Constellation map[Coordinate]struct{}
+
+func (c Constellation) Distance(b Coordinate) int {
+	shortestDistance := math.MaxInt64
+
+	for p := range c {
+		if p.Distance(b) < shortestDistance {
+			shortestDistance = p.Distance(b)
+		}
+	}
+
+	return shortestDistance
+}
+
+func (c Constellation) CelestialDistance(b Constellation) int {
+	shortestDistance := math.MaxInt64
+
+	for p := range c {
+		if b.Distance(p) < shortestDistance {
+			shortestDistance = b.Distance(p)
+		}
+	}
+
+	return shortestDistance
+}
+
+func (c Constellation) Add(b Coordinate) {
+	c[b] = struct{}{}
+}
+
+func (c Constellation) Merge(b Constellation) {
+	for p := range b {
+		c[p] = struct{}{}
+		delete(b, p)
+	}
+}
+
+func NewConstellation(b Coordinate) Constellation {
+	c := Constellation{b: struct{}{}}
+	return c
+}