added singly circular linked list

README.md

@@ -12,6 +12,7 @@ ChangeLog:
 * 2014-09-14 fixed InsertLast() and Print() method in singly linked list, added doubly linked list (Dikaimin)
 * 2014-09-16 added queue (Rizal)
 * 2014-09-16 fixed SliceQueue (Dikaimin)
+* 2014-09-22 added singly circular linked list (Dikaimin)
 
 TODO:
 =====
@@ -21,9 +22,8 @@ TODO:
 BOUNTY:
 =======
 
-* implement SingleCircularLinkedList, DoubleCircularLinkedList +150 each
+* implement DoubleCircularLinkedList +150 each
 * implement UnrolledSinglyLinkedList, UnrolledDoubleLinkedList +200 each
 * implement VList +300
 * implement Skiplist +350
 * implement SliceDeque +200 (use 2 slice for always O(1) operations)
-

SinglyCircularLinkedList.go

@@ -0,0 +1,205 @@
+/*
+    Singly Circular Linked List Interface
+*/
+
+package main
+
+import "fmt"
+
+type Any interface{}
+
+type Node struct {
+    Data Any
+    NextLink *Node
+}
+
+// Return data: O(1)
+func (n *Node) GetData() Any {
+    return n.Data
+}
+
+// Set data: O(1)
+func (n *Node) SetData(data Any) {
+    n.Data = data
+}
+
+// Return next node: O(1)
+func (n *Node) GetNext() *Node {
+    return n.NextLink
+}
+
+// Set next node: O(1)
+func (n *Node) SetNext(next *Node) {
+    n.NextLink = next
+}
+
+// Test whether node has next node: O(1)
+func (n *Node) HasNext() bool {
+    if n.NextLink == nil { return false }
+    return true
+}
+
+type SCLL struct {
+    Head *Node
+    count int
+}
+
+// Create a new Singly Circular Linked List: O(1)
+func NewSCLL() *SCLL {
+    return &SCLL{}
+}
+
+// Return size: O(1)
+func (s *SCLL) Count() int {
+    return s.count
+}
+
+// Return last node: O(N)
+func (s *SCLL) GetTail() *Node {
+    if s.Head == nil { return nil }
+    current := s.Head
+    for current.GetNext() != s.Head {
+        current = current.GetNext()
+    }
+    return current
+}
+
+// Insert as head, set old head as head's prev: O(1)
+func (s *SCLL) InsertPrev(newnode *Node) {
+    if s.Head == nil {
+        s.Head = newnode
+        newnode.SetNext(newnode)
+        s.count++
+        return
+    }
+    next := s.Head.GetNext()
+    newnode.SetNext(next)
+    s.Head.SetNext(newnode)
+    s.Head = newnode
+    s.count++
+}
+
+// Insert as head, set old head as head's next: O(N)
+func (s *SCLL) InsertNext(newnode *Node) {
+    if s.Head == nil {
+        s.Head = newnode
+        newnode.SetNext(newnode)
+        s.count++
+        return
+    }
+    tail := s.GetTail()
+    tail.SetNext(newnode)
+    newnode.SetNext(s.Head)
+    s.Head = newnode
+    s.count++
+}
+
+// Delete head, set head's prev as new head: O(N)
+func (s *SCLL) DeletePrev() {
+    if s.Head != nil {
+        if s.count == 1 {
+            s.Head = nil
+            s.count--
+            return
+        }
+        tail := s.GetTail()
+        tail.SetNext(s.Head.GetNext())
+        s.Head = tail
+        s.count--
+    }
+}
+
+// Delete head, set head's next as new head: O(N)
+func (s *SCLL) DeleteNext() {
+    if s.Head != nil {
+        if s.count == 1 {
+            s.Head = nil
+            s.count--
+            return
+        }
+        tail := s.GetTail()
+        tail.SetNext(s.Head.GetNext())
+        s.Head = s.Head.GetNext()
+        s.count--
+    }
+}
+
+// Set head's next as new head: O(1)
+func (s *SCLL) RotateLeft() {
+    if s.Head != nil {
+        s.Head = s.Head.GetNext()
+    }
+}
+
+// Set head's prev as new head: O(N)
+func (s *SCLL) RotateRight() {
+    if s.Head != nil {
+        s.Head = s.GetTail()
+    }
+}
+
+// Print to left: O(N)
+func (s *SCLL) PrintToLeft() {
+    if s.Head == nil {
+        fmt.Println("| Empty |")
+        return
+    }
+    current := s.Head
+    fmt.Printf("| %#v |", current.Data)
+    defer fmt.Println()
+    current = current.GetNext()
+    for current != s.Head {
+        defer fmt.Printf(" %#v |", current.Data)
+        current = current.GetNext()
+    }
+}
+
+// Print to right: O(N)
+func (s *SCLL) PrintToRight() {
+    if s.Head == nil {
+        fmt.Println("| Empty |")
+        return
+    }
+    current := s.Head
+    fmt.Print("|")
+    for {
+        fmt.Printf(" %#v |", current.Data)
+        current = current.GetNext()
+        if current == s.Head { break }
+    }
+    fmt.Println()
+}
+
+func main() {
+    s := NewSCLL()
+    fmt.Println("Initial condition:")
+    s.PrintToRight()
+
+    for i := 1; i <= 3; i++ {
+        fmt.Printf("\nInsert %d as head and set old head as head's next\n",i)
+        s.InsertNext(&Node{i, nil})
+        s.PrintToRight()
+    }
+
+    for i := 4; i <= 6; i++ {
+        fmt.Printf("\nInsert %d as head and set old head as head's prev\n",i)
+        s.InsertPrev(&Node{i, nil})
+        s.PrintToRight()
+    }
+
+    for i := 0; i < 2; i++ {
+        fmt.Printf("\nRotate left:\n")
+        s.RotateLeft()
+        s.PrintToRight()
+    }
+
+    fmt.Printf("\nRotate right:\n")
+    s.RotateRight()
+    s.PrintToRight()
+
+    fmt.Printf("\nPrint to right:\n")
+    s.PrintToRight()
+
+    fmt.Printf("\nPrint to left:\n")
+    s.PrintToLeft()
+}