Adding doublylinkedlist in go

Author: bhavnavarshney

Go/linkedlist/doublyLinkedList.go

@@ -0,0 +1,110 @@
+package linkedlist
+
+import "fmt"
+
+type DoublyNode struct {
+	Val  int
+	Next *DoublyNode
+	Prev *DoublyNode
+}
+
+type DoublyLinkedList struct {
+	Head *DoublyNode
+	Len  int
+}
+
+func (l *DoublyLinkedList) Print(msg string) {
+	pointer := l.Head
+	fmt.Println("\n*** PRINTING:", msg, " ****\n")
+	for pointer != nil {
+		fmt.Print(pointer.Prev, "[", pointer.Val, "]", pointer.Next, "| -> |")
+		pointer = pointer.Next
+	}
+}
+
+func (l *DoublyLinkedList) InsertAtEnd(val int) {
+	n := &DoublyNode{Val: val, Next: nil, Prev: nil}
+	if l.Head == nil {
+		l.Head = n
+		return
+	}
+
+	pointer := l.Head
+	previous := pointer
+	for pointer != nil {
+		previous = pointer
+		pointer = pointer.Next
+	}
+	previous.Next = n
+	n.Prev = previous
+}
+
+func (l *DoublyLinkedList) InsertAtStart(val int) {
+	n := &DoublyNode{Val: val, Prev: nil, Next: nil}
+	if l.Head == nil {
+		l.Head = n
+		return
+	}
+
+	l.Head.Prev = n
+	tempHead := l.Head
+	l.Head = n
+	l.Head.Next = tempHead
+}
+
+func (l *DoublyLinkedList) DeleteAtStart() {
+	if l.Head == nil {
+		return
+	}
+	previous := l.Head.Prev
+	l.Head = l.Head.Next
+	l.Head.Prev = previous
+}
+
+func (l *DoublyLinkedList) InsertAtIndex(index, val int) {
+	count := 0
+	n := &DoublyNode{Val: val, Next: nil, Prev: nil}
+	pointer := l.Head
+	previous := pointer
+
+	for ; pointer != nil; count++ {
+		if count == index {
+			n.Next = previous.Next
+			n.Prev = previous
+			previous.Next = n
+			pointer.Prev = n
+			return
+		}
+		previous = pointer
+		pointer = pointer.Next
+
+	}
+}
+
+func (l *DoublyLinkedList) DeleteAtEnd() {
+	if l.Head == nil {
+		return
+	}
+	pointer := l.Head
+	previous := pointer
+	for pointer.Next != nil {
+		previous = pointer
+		pointer = pointer.Next
+	}
+	previous.Next = nil
+}
+
+func (l *DoublyLinkedList) DeleteAtIndex(index int) {
+	count := 0
+	pointer := l.Head
+	previous := pointer
+
+	for ; pointer != nil; count++ {
+		if count == index {
+			previous.Next = pointer.Next
+			pointer.Prev = previous
+		}
+		previous = pointer
+		pointer = pointer.Next
+	}
+}

Go/linkedlist/singleLinkedList.go

@@ -78,7 +78,7 @@ func (l *SinglyLinkedList) DeleteAtEnd() {
 	}
 	pointer := l.Head
 	previous := pointer
-	for pointer.Next == nil {
+	for pointer.Next != nil {
 		previous = pointer
 		pointer = pointer.Next
 	}

Go/main.go

@@ -13,10 +13,26 @@ func main() {
 	l.InsertAtStart(100)
 	l.InsertAtEnd(200)
 	l.InsertAtIndex(1, 3)
-	l.Print()          // 100 3 5 200
-	l.DeleteAtIndex(2) // 100 3 200
-	l.DeleteAtStart()  // 3 200
-	l.DeleteAtEnd()    // 3
+	l.Print()            // 100 3 5 200
+	l.DeleteAtIndex(2)   // 100 3 200
+	l.DeleteAtStart()    // 3 200
+	l.InsertAtStart(100) // 100 3 200
+	l.DeleteAtEnd()      // 100 3
 	l.Print()
 
+	fmt.Println("\n***** Doubly LinkedList *******")
+	l2 := linkedlist.DoublyLinkedList{}
+	l2.InsertAtEnd(5)     //5
+	l2.InsertAtStart(100) //100 5
+	l2.Print("Insertion at Start & End")
+	l2.InsertAtEnd(200) // 100 5 200
+	l2.Print("Insertion at End")
+	l2.DeleteAtStart()      // 5 200
+	l2.InsertAtIndex(1, 10) // 5 10 200
+	l2.Print("Deletion at Start and Insert at Index")
+	l2.DeleteAtEnd()
+	l2.Print("Delete at End") // 5 10
+	l2.DeleteAtIndex(1)
+	l2.Print("Delete at Index 1") // 5
+
 }