1. More on Linked List Yumei Huo Department of Computer Science
Sequences
2019/7/24
More on Linked List
Yumei Huo
Department of Computer Science
College of Staten Island, CUNY
Spring 2009
2019/7/24
Linked list

2. Outline Variants of Singly linked list Doubly linked list 2019/7/24

3. Outline Variants of Singly linked list Doubly linked list 2019/7/24

4. Variants of Singly linked list
Singly linked circular list
Singly linked list with head node
Singly linked circular list with head node
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Linked list

5. Singly linked circular list
Link the last node back to the first A B C D
first E
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Linked list

6. Print all the elements in a singly linked circular listB C D
first E
Node * tmp=first;
if (tmp != 0) {
cout << tmp->data;
while (tmp->next !=first)
tmp=tmp->next; }
2019/7/24
Linked list

7. Singly linked list with head node
Add an additional node, called head node, at the front
first 
Head node
Empty list A B C
first 
Head node
Singly linked list with head node
2019/7/24
Linked list

8. Singly linked circular list with head node
first
Head node
Empty list A B C
first
Head node
Circular list with head node
2019/7/24
Linked list

9. Outline Variants of Singly linked list Doubly linked list 2019/7/24

10. Doubly Linked List Nodes implement Position and store: data
link to the previous node
link to the next node
prev
next
data
node
Tail
Head A B C D
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Linked list

11. Operations Comparison
Singly Linked List
Doubly Linked List
Determine the length
O(n)
Find the kth element
O(k)
Search for a given element
Delete the kth element
Insert a new element just after the kth
Delete a node pointed by p
O(1)
Insert a new element before the node pointed by p
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Linked list

12. Delete a node pointed by pq
Head
Tail A B C D q
Tail
Head A B C D q
Tail
Head A B D
Doubly Linked List p q
Head A B C D q
Head A B C D q
Head A B D
Singly Linked List
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Linked list

13. Delete a node pointed by p in a doubly linked listq
Head
Tail A B C D q
Tail
Head A B C D q
Tail
Head A B D
Doubly Linked List
p->prev->next=p->next;
p->next->prev=p->prev;
delete p;
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Linked list

14. Delete a node pointed by p in singly linked listq
Head A B C D q
Head A B C D q
Head A B D
Singly Linked List
//search p’s previous node q, assume p exists and is not the 1st node
//(what if p is the 1st node?):
Node * q=head;
while (q->next != p)
q=q->next;
//let q point to p’s next node
q->next=p->next;
delete p;
2019/7/24
Linked list

15. Insert a new element ‘X’ before the node pointed by p
Head A B C
Tail t p
Head A B C
Tail X q t q p
Head A B X C
Tail
Doubly Linked List t p
Head A B C p t
Head A B C q X t q p
Head A B X C
Singly Linked List
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Linked list

16. Sequences
2019/7/24
Insert a new element ‘X’ before the node pointed by p in a doubly linked list t p
Head A B C
Tail t p
Head A B C
Tail X q t q p
Head A B X C
Tail
Doubly Linked List
//create a new node containing ‘X’:
Node *q = new Node;
q->data=‘X’;
//insert q before p:
q->prev=p->prev;
q->next=p;
p->prev->next=q;
p->prev=q;
2019/7/24
Linked list

17. Insert a new element ‘X’ before the node pointed by p in a singly linked list
Head A B C p t
Head A B C q X t q p
Head A B X C
Singly Linked List
//create a new node containing ‘X’:
Node * q= new Node;
Q->data = ‘X’;
//search p’s previous node t, assume p exists and is not the 1st node
//(what if p is the 1st node?):
Node * t= head;
while (q->next != p)
q=q->next;
//insert q between t and p
q->next=p;
t->next=q;
2019/7/24
Linked list

18. Thank you!
2019/7/24
Linked list