Babylonian spiral: Difference between revisions

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 === iterator version ===
 See Python iterator version.
-<syntaxhighlight lang="julia">using Plots
+<syntaxhighlight lang="julia">using DataStructures
+using Plots
 struct SquareSums end
-function Base.iterate(ss::SquareSums, state = (1, Tuple{Int, Int, Int}[]))
+function Base.iterate(ss::SquareSums, state = (1, PriorityQueue{Tuple{Int, Int, Int}, Int}()))
     i, sums = state
-    while isempty(sums) || i^2 <= sums[1][1]
+    while isempty(sums) || i^2 <= peek(sums)[2]
-        push!(sums, (i^2, i, 0))
+        enqueue!(sums, (i^2, i, 0) => i^2)
         i += 1
     end
+    nextsum, xy = peek(sums)[2], Tuple{Int, Int}[]
-    sort!(sums)
+    while !isempty(sums) && peek(sums)[2] == nextsum # pop all vectors with same length
-    nextsum, xy = sums[1][1], Tuple{Int, Int}[]
-    while !isempty(sums) && sums[1][1] == nextsum # pop all vectors with same length
+        nextsum, a, b = dequeue!(sums)
-        nextsum, a, b = popfirst!(sums)
         push!(xy, (a, b))
         if a > b
-            push!(sums, (a^2 + (b + 1)^2, a, b + 1))
+            hsq = a^2 + (b + 1)^2
+            enqueue!(sums, (hsq, a, b + 1) => hsq)
         end
     end