Initial data commit

Task/Sorting-algorithms-Heapsort/NetRexx/sorting-algorithms-heapsort.netrexx

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+/* NetRexx */
+options replace format comments java crossref savelog symbols binary
+
+import java.util.List
+
+placesList = [String -
+    "UK  London",     "US  New York",   "US  Boston",     "US  Washington" -
+  , "UK  Washington", "US  Birmingham", "UK  Birmingham", "UK  Boston"     -
+]
+
+lists = [ -
+    placesList -
+  , heapSort(String[] Arrays.copyOf(placesList, placesList.length)) -
+]
+
+loop ln = 0 to lists.length - 1
+  cl = lists[ln]
+  loop ct = 0 to cl.length - 1
+    say cl[ct]
+    end ct
+    say
+  end ln
+
+return
+
+method heapSort(a = String[], count = a.length) public constant binary returns String[]
+
+
+  rl = String[a.length]
+  al = List heapSort(Arrays.asList(a), count)
+  al.toArray(rl)
+
+  return rl
+
+method heapSort(a = List, count = a.size) public constant binary returns ArrayList
+
+  a = heapify(a, count)
+
+  iend = count - 1
+  loop label iend while iend > 0
+    swap = a.get(0)
+    a.set(0, a.get(iend))
+    a.set(iend, swap)
+    a = siftDown(a, 0, iend - 1)
+    iend = iend - 1
+    end iend
+
+  return ArrayList(a)
+
+method heapify(a = List, count = int) public constant binary returns List
+
+  start = (count - 2) % 2
+
+  loop label strt while start >= 0
+    a = siftDown(a, start, count - 1)
+    start = start - 1
+    end strt
+
+  return a
+
+method siftDown(a = List, istart = int, iend = int) public constant binary returns List
+
+  root = istart
+
+  loop label root while root * 2 + 1 <= iend
+    child = root * 2 + 1
+    if child + 1 <= iend then do
+      if (Comparable a.get(child)).compareTo(Comparable a.get(child + 1)) < 0 then do
+        child = child + 1
+        end
+      end
+    if (Comparable a.get(root)).compareTo(Comparable a.get(child)) < 0 then do
+      swap = a.get(root)
+      a.set(root, a.get(child))
+      a.set(child, swap)
+      root = child
+      end
+    else do
+      leave root
+      end
+    end root
+
+  return a