Day 12 solution

Okay, I had to seek some advice on this one. The orbital period + least-common-multiple solution was not coming to me naturally.

utilities/math.go

@@ -0,0 +1,27 @@
+package utilities
+
+func GCD[T Integer](a, b T) T {
+	if b == 0 {
+		return a
+	}
+	return GCD(b, a%b)
+}
+
+func LCM[T Integer](nums ...T) uint64 {
+	num := len(nums)
+	if num == 0 {
+		return 0
+	} else if num == 1 {
+		return uint64(nums[0])
+	}
+
+	ret := lcm(nums[0], nums[1])
+	for i := 2; i < len(nums); i++ {
+		ret = lcm(uint64(nums[i]), ret)
+	}
+	return ret
+}
+
+func lcm[T Integer](a, b T) uint64 {
+	return uint64(a*b) / uint64(GCD(a, b))
+}