update

Task/Sorting-algorithms-Pancake-sort/NetRexx/sorting-algorithms-pancake-sort.netrexx

@@ -0,0 +1,81 @@
+/* NetRexx */
+options replace format comments java crossref symbols nobinary
+
+import java.util.List
+
+runSample(arg)
+return
+
+-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+method pancakeSort(tlist = List, debug = (1 == 0)) private static returns List
+
+  if tlist.size() > 1 then do
+    loop i_ = tlist.size() by -1 while i_ > 1
+      maxPos = 0
+      loop a_ = 0 while a_ < i_
+        if Rexx tlist.get(a_) > Rexx tlist.get(maxPos) then maxPos = a_
+        end a_
+      if maxPos = i_ - 1 then iterate i_
+      if maxPos > 0 then pancakeFlip(tlist, maxPos + 1, debug)
+      pancakeFlip(tlist, i_, debug)
+      end i_
+    end
+  return tlist
+
+-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+method pancakeFlip(tlist = List, offset, debug = (1 == 0)) private static returns List
+  z_ = offset - 1
+  pl = 3
+  if debug then do
+    plx = offset.length()
+    if plx > pl then pl = plx
+    say '  flip{1-'offset.right(pl, 0)'} Before:' tlist
+    end
+  loop i_ = 0 while i_ < z_
+    Collections.swap(tlist, i_, z_)
+    z_ = z_ - 1
+    end i_
+  if debug then do
+    say '  flip{1-'offset.right(pl, 0)'}  After:' tlist
+    end
+  return tlist
+
+-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+method runSample(arg) private static
+
+  isTrue  = (1 == 1)
+  isFalse = \isTrue
+
+  parse arg debug .
+  if '-debug'.abbrev(debug.lower(), 2) then debug = isTrue
+  else                                      debug = isFalse
+
+  lists = sampleData()
+  loop il = 1 to lists[0]
+    clist = words2list(lists[il])
+    say ' Input:' clist
+    say 'Output:' pancakeSort(clist, debug)
+    say
+    end il
+
+  return
+-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+method sampleData() private static
+  lists = ''
+  i_ = 0
+  i_ = i_ + 1; lists[0] = i_; lists[i_] = '1 4 3 5 2 9 8 7 6'
+  i_ = i_ + 1; lists[0] = i_; lists[i_] = '10 -9 8 -7 6 -5 4 -3 2 -1 0 -10 9 -8 7 -6 5 -4 3 -2 1'
+  i_ = i_ + 1; lists[0] = i_; lists[i_] = '88 18 31 44 4 0 8 81 14 78 20 76 84 33 73 75 82 5 62 70 12 7 1'
+  i_ = i_ + 1; lists[0] = i_; lists[i_] = '10 10.0 10.00 1 -10.0 10. -1'
+  i_ = i_ + 1; lists[0] = i_; lists[i_] = 'To be or not to be that is the question'
+  i_ = i_ + 1; lists[0] = i_; lists[i_] = '1'
+  return lists
+-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+method words2list(wordlist) private static returns List
+
+  clist = ArrayList()
+  loop w_ = 1 to wordlist.words()
+    clist.add(wordlist.word(w_))
+    end w_
+
+  return clist

Task/Sorting-algorithms-Pancake-sort/Racket/sorting-algorithms-pancake-sort.rkt

@@ -0,0 +1,12 @@
+#lang racket
+
+(define (pancake-sort l)
+  (define (flip l n) (append (reverse (take l n)) (drop l n)))
+  (for/fold ([l l]) ([i (in-range (length l) 1 -1)])
+    (let* ([i2 (cdr (for/fold ([m #f]) ([x l] [j i])
+                      (if (and m (<= x (car m))) m (cons x j))))]
+           [l (if (zero? i2) l (flip l (add1 i2)))])
+      (flip l i))))
+
+(pancake-sort (shuffle (range 0 10)))
+;; => '(0 1 2 3 4 5 6 7 8 9)

Task/Sorting-algorithms-Pancake-sort/Ruby/sorting-algorithms-pancake-sort.rb

@@ -1,28 +1,19 @@
 class Array
   def pancake_sort!
     num_flips = 0
-    self.size.downto(2) do |i|
-      end_idx = i - 1
-      max_idx = self[0..end_idx].each_with_index.max_by {|e| e[0]}.last
+    (self.size-1).downto(1) do |end_idx|
+      max     = self[0..end_idx].max
+      max_idx = self[0..end_idx].index(max)
       next if max_idx == end_idx
 
       if max_idx > 0
         self[0..max_idx] = self[0..max_idx].reverse
-
-        if $DEBUG
-          num_flips += 1
-          p [num_flips, self]
-        end
+        p [num_flips += 1, self]  if $DEBUG
       end
 
       self[0..end_idx] = self[0..end_idx].reverse
-
-      if $DEBUG
-        num_flips += 1
-        p [num_flips, self]
-      end
+      p [num_flips += 1, self]  if $DEBUG
     end
-
     self
   end
 end