Data commit

Task/Permutations-by-swapping/PowerShell/permutations-by-swapping.psh

@@ -0,0 +1,37 @@
+function output([Object[]]$A, [Int]$k, [ref]$sign)
+{
+    "Perm: [$([String]::Join(', ', $A))] Sign: $($sign.Value)"
+}
+
+function permutation([Object[]]$array)
+{
+    function generate([Object[]]$A, [Int]$k, [ref]$sign)
+    {
+        if($k -eq 1)
+        {
+            output $A $k $sign
+            $sign.Value = -$sign.Value
+        }
+        else
+        {
+            $k -= 1
+            generate $A  $k $sign
+            for([Int]$i = 0; $i -lt $k; $i += 1)
+             {
+                if($i % 2 -eq 0)
+                {
+                    $A[$i], $A[$k] = $A[$k], $A[$i]
+                }
+                else
+                {
+                    $A[0], $A[$k] = $A[$k], $A[0]
+                }
+                generate $A $k $sign
+            }
+        }
+    }
+    generate $array $array.Count ([ref]1)
+}
+permutation @(0, 1, 2)
+""
+permutation @(0, 1, 2, 3)