June 2018 Update

Task/Hailstone-sequence/Julia/hailstone-sequence-1.julia

@@ -0,0 +1,11 @@
+function hailstonelength(n::Integer)
+	len = 1
+	while n > 1
+		n = ifelse(iseven(n), n ÷ 2, 3n + 1)
+		len += 1
+	end
+	return len
+end
+
+@show hailstonelength(27)
+@show findmax(hailstonelength(i) for i in 1:100_000)

Task/Hailstone-sequence/Julia/hailstone-sequence-2.julia

@@ -0,0 +1,40 @@
+struct HailstoneSeq{T<:Integer}
+	start::T
+end
+
+Base.eltype(::HailstoneSeq{T}) where T = T
+
+Base.start(hs::HailstoneSeq) = (-1, hs.start)
+Base.done(::HailstoneSeq, state) = state == (1, 4)
+function Base.next(::HailstoneSeq, state)
+	_, s2 = state
+	s1 = s2
+	if iseven(s2)
+		s2 = s2 ÷ 2
+	else
+		s2 = 3s2 + 1
+	end
+	return s1, (s1, s2)
+end
+
+function Base.length(hs::HailstoneSeq)
+	r = 0
+	for _ in hs
+		r += 1
+	end
+	return r
+end
+
+function Base.show(io::IO, hs::HailstoneSeq)
+	f5 = collect(Iterators.take(hs, 5))
+	print(io, "HailstoneSeq(", join(f5, ", "), "...)")
+end
+
+hs = HailstoneSeq(27)
+println("Collection of the Hailstone sequence from 27: $hs")
+cl = collect(hs)
+println("First 5 elements: ", join(cl[1:5], ", "))
+println("Last 5 elements: ", join(cl[end-4:end], ", "))
+
+Base.isless(h::HailstoneSeq, s::HailstoneSeq) = length(h) < length(s)
+println("The number with the longest sequence under 100,000 is: ", maximum(HailstoneSeq.(1:100_000)))

Task/Hailstone-sequence/Julia/hailstone-sequence-3.julia

@@ -0,0 +1,40 @@
+struct HailstoneSeq{T<:Integer}
+	start::T
+end
+
+Base.eltype(::HailstoneSeq{T}) where T = T
+
+Base.start(hs::HailstoneSeq) = (-1, hs.start)
+Base.done(::HailstoneSeq, state) = state == (1, 4)
+function Base.next(::HailstoneSeq, state)
+	_, s2 = state
+	s1 = s2
+	if iseven(s2)
+		s2 = s2 ÷ 2
+	else
+		s2 = 3s2 + 1
+	end
+	return s1, (s1, s2)
+end
+
+function Base.length(hs::HailstoneSeq)
+	r = 0
+	for _ in hs
+		r += 1
+	end
+	return r
+end
+
+function Base.show(io::IO, hs::HailstoneSeq)
+	f5 = collect(Iterators.take(hs, 5))
+	print(io, "HailstoneSeq(", join(f5, ", "), "...)")
+end
+
+hs = HailstoneSeq(27)
+println("Collection of the Hailstone sequence from 27: $hs")
+cl = collect(hs)
+println("First 5 elements: ", join(cl[1:5], ", "))
+println("Last 5 elements: ", join(cl[end-4:end], ", "))
+
+Base.isless(h::HailstoneSeq, s::HailstoneSeq) = length(h) < length(s)
+println("The number with the longest sequence under 100,000 is: ", maximum(HailstoneSeq.(1:100_000)))

Task/Hailstone-sequence/Julia/hailstone-sequence.julia

@@ -1,8 +0,0 @@
-function hailstone(n)
-	seq = [n]
-	while n>1
-		n = n % 2 == 0 ? n >> 1 : 3n + 1
-		push!(seq,n)
-	end
-	return seq
-end