September Morn Update

Task/Quickselect-algorithm/Factor/quickselect-algorithm.factor

@@ -0,0 +1,18 @@
+USING: combinators kernel make math locals prettyprint sequences ;
+IN: rosetta-code.quickselect
+
+:: quickselect ( k seq -- n )
+    seq unclip :> ( xs x )
+    xs [ x < ] partition :> ( ys zs )
+    ys length :> l
+    {
+        { [ k l < ] [ k ys quickselect ] }
+        { [ k l > ] [ k l - 1 - zs quickselect ] }
+        [ x ]
+    } cond ;
+
+: quickselect-demo ( -- )
+    { 9 8 7 6 5 0 1 2 3 4 } dup length <iota> swap
+    [ [ quickselect , ] curry each ] { } make . ;
+
+MAIN: quickselect-demo