update

Task/Sorting-algorithms-Permutation-sort/Java/sorting-algorithms-permutation-sort.java

@@ -0,0 +1,52 @@
+import java.util.List;
+import java.util.ArrayList;
+import java.util.Arrays;
+
+public class PermutationSort
+{
+	public static void main(String[] args)
+	{
+		int[] a={3,2,1,8,9,4,6};
+		System.out.println("Unsorted: " + Arrays.toString(a));
+		a=pSort(a);
+		System.out.println("Sorted: " + Arrays.toString(a));
+	}
+	public static int[] pSort(int[] a)
+	{
+		List<int[]> list=new ArrayList<int[]>();
+		permute(a,a.length,list);
+		for(int[] x : list)
+			if(isSorted(x))
+				return x;
+		return a;
+	}
+	private static void permute(int[] a, int n, List<int[]> list)
+	{
+		if (n == 1)
+		{
+			int[] b=new int[a.length];
+			System.arraycopy(a, 0, b, 0, a.length);
+			list.add(b);
+		    return;
+		}
+		for (int i = 0; i < n; i++)
+		{
+		        swap(a, i, n-1);
+		        permute(a, n-1, list);
+		        swap(a, i, n-1);
+		 }
+	}
+	private static boolean isSorted(int[] a)
+	{
+		for(int i=1;i<a.length;i++)
+			if(a[i-1]>a[i])
+				return false;
+		return true;
+	}
+	private static void swap(int[] arr,int i, int j)
+	{
+		int temp=arr[i];
+		arr[i]=arr[j];
+		arr[j]=temp;
+	}
+}

Task/Sorting-algorithms-Permutation-sort/NetRexx/sorting-algorithms-permutation-sort.netrexx

@@ -0,0 +1,84 @@
+/* NetRexx */
+options replace format comments java crossref symbols nobinary
+
+import java.util.List
+import java.util.ArrayList
+
+numeric digits 20
+
+class RSortingPermutationsort public
+
+  properties private static
+    iterations
+    maxIterations
+
+  -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  method permutationSort(vlist = List) public static returns List
+    perm = RPermutationIterator(vlist)
+    iterations = 0
+    maxIterations = RPermutationIterator.factorial(vlist.size())
+    loop while perm.hasNext()
+      iterations = iterations + 1
+      pl = List perm.next()
+      if isSorted(pl) then leave
+      else pl = null
+      end
+    return pl
+
+  -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  method isSorted(ss = List) private static returns boolean
+    status = isTrue
+    loop ix = 1 while ix < ss.size()
+      vleft  = Rexx ss.get(ix - 1)
+      vright = Rexx ss.get(ix)
+      if vleft.datatype('N') & vright.datatype('N')
+      then vtest = vleft > vright  -- For numeric types we must use regular comparison.
+      else vtest = vleft >> vright -- For non-numeric/mixed types we must do strict comparison.
+      if vtest then do
+        status = isFalse
+        leave ix
+        end
+      end ix
+    return status
+
+  -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  method runSample(arg) private static
+    placesList = -
+        "UK  London,     US  New York,   US  Boston,     US  Washington" -
+        "UK  Washington, US  Birmingham, UK  Birmingham, UK  Boston"
+    anotherList = 'Alpha, Beta, Gamma, Beta'
+    reversed = '7, 6, 5, 4, 3, 2, 1'
+    unsorted = '734, 3, 1, 24, 324, -1024, -666, -1, 0, 324, 99999999'
+    lists = [makeList(placesList), makeList(anotherList), makeList(reversed), makeList(unsorted)]
+    loop il = 0 while il < lists.length
+      vlist = lists[il]
+      say vlist
+      runtime = System.nanoTime()
+      rlist = permutationSort(vlist)
+      runtime = System.nanoTime() - runtime
+      if rlist \= null then say rlist
+      else say 'sort failed'
+      say 'This permutation sort of' vlist.size() 'elements took' iterations 'passes (of' maxIterations') to complete. \-'
+      say 'Elapsed time:' (runtime / 10 ** 9)'s.'
+      say
+      end il
+    return
+
+  -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  method makeList(in) public static returns List
+    lst = ArrayList()
+    loop while in > ''
+      parse in val ',' in
+      lst.add(val.strip())
+      end
+    return lst
+  -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  method main(args = String[]) public static
+    runSample(Rexx(args))
+    return
+  -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  method isTrue() public static returns boolean
+    return (1 == 1)
+  -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  method isFalse() public static returns boolean
+    return (1 == 0)

Task/Sorting-algorithms-Permutation-sort/Racket/sorting-algorithms-permutation-sort.rkt

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+#lang racket
+(define (sort l)
+  (for/first ([p (in-permutations l)] #:when (apply <= p)) p))
+(sort '(6 1 5 2 4 3)) ; => '(1 2 3 4 5 6)