4 Smalltalk scripts, 2 Perl scripts

1 files changed, 121 insertions, 0 deletions

diff --git a/challenge-068/cheok-yin-fung/smalltalk/ch-2.st b/challenge-068/cheok-yin-fung/smalltalk/ch-2.st
new file mode 100644
index 0000000000..f4010ea6b6
--- /dev/null
+++ b/challenge-068/cheok-yin-fung/smalltalk/ch-2.st
@@ -0,0 +1,121 @@
+"GNU Smalltalk 3.2.5"
+"The Weekly Challenge 068 Task 2"
+"Reorder List"
+"Usage: gst -S ch-2.st"
+"written on 30th Jan 2021"
+"Smalltalk has built-in Linked List, 
+here is reventing the wheel."
+
+
+Object subclass: Node [
+  |value next|
+  Node class >> value: v next: n [
+    <category: 'instance creation'> 
+   ^(super new) setValue: v setNext: n
+  ]
+  value [
+    ^value
+  ]
+
+  setValue: v setNext: n [
+     value := v.
+     next := n.
+     ^self
+  ]
+
+  setValue: v [
+     <category: 'basic'> 
+     value := v.
+     ^self
+  ]
+  next [
+    ^next
+  ]
+  setNext: n [
+    <category: 'basic'> 
+    next := n.
+    ^next
+  ]
+  setNextnil [
+    next := nil.
+  ]
+]
+
+Object subclass: SLL [
+  |root|
+  SLL class >> root: node [
+    <category: 'instance creation'>
+    ^(super new) setRoot: node
+  ]
+  root [
+     ^root
+  ]
+  setRoot: node [
+    <category: 'basic'>
+    root := node.
+  ]
+  showList [  
+    |myNode|
+    myNode := root.
+    [myNode next isNil not] whileTrue:[
+      (myNode value displayString,  ' ' ) print. 
+      myNode := myNode next.
+    ].
+    myNode value printNl.
+  ]
+]
+
+i := Node value: 23 next: nil.
+h := Node value: 19 next: i.
+g := Node value: 17 next: h.
+f := Node value: 13 next: g.
+e := Node value: 11 next: f.
+d := Node value:  7 next: e.
+c := Node value:  5 next: d.
+b := Node value:  3 next: c.
+a := Node value:  2 next: b.
+
+abc := SLL root: a.
+
+'Before operation' printNl.
+abc showList.
+
+listsize := 1.
+
+traveller := abc root.
+[traveller next isNil not] whileTrue:[
+  listsize := listsize + 1.
+  traveller := traveller next.
+].
+listTail := traveller.
+
+
+nodeHandle := abc root.
+
+(listsize - 1 // 2) timesRepeat: [
+  traveller := abc root.
+  [( traveller next == listTail ) not ] whileTrue: [
+    traveller := traveller next.
+  ].
+  preListTail := traveller.
+  
+  waiter := nodeHandle next.
+  preListTail setNextnil.
+  nodeHandle setNextnil.
+  guestSeat := listTail.
+  nodeHandle setNext: guestSeat.
+  listTail := preListTail.
+  guestSeat setNext: waiter.  
+  
+  (nodeHandle next isNil) ifFalse: [
+    (nodeHandle next isNil not) ifTrue:
+      [nodeHandle := nodeHandle next next.]
+  ].
+].
+
+'After operation' printNl.
+
+abc showList.
+
+ObjectMemory quit.
+