1. Lists List L = x0 x1 x2 x3 … xn-1 n = # elements
If a list is ordered than the key of xi-1 <= the key of xi for all i where 0 < i < n.
The sort symbol <= can be replaced by >= or any other function that determines
ordering in the keys.
An unordered list does not have this restriction.
Functions:
access(L, i) returns xi
length(L) returns n
concat(L1, L2) returns a new list with L2 concatenated on to L1
createEmptyList() returns a newly created empty list
isEmptyList(L) returns true if L is empty and false if it is not
searchFor(L, key) returns i where the key of xi = key
remove(L, i) returns a list with xi removed; the old xi+1 is now xi, etc.
inserti(L, i, x) returns a list with x inserted as xi; the old xi is now xi+1, etc.
insert(L, x) returns a list with x added to L
sort(L) returns the list in sorted order

2. A Node With Pointer NameLast: Smart FirstName: Joe StudentNumber: 8
SSN:
Grade: 95

3. Homework 1
Describe how to use a set of nodes with pointers (as described in class) to implement a variable length unordered list.
Determine how to do the following functions: access, length, concat, createEmptyList, isEmptyList, searchFor, remove, inserti, and insert.
How would any of these functions change if the list was to be ordered?

4. Linked List
head
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
when we pass a list in as a parameter we pass in the head
a pointer pointing to null indicates the end of the list
null
is a node pointer which is part of the node, we’ll call it next

5. Linked List with Tail tail head null NameLast: Smart FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
null

6. Linked List
head
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
when we pass a list in as a parameter we pass in the head
a pointer pointing to null indicates the end of the list
null
is a node pointer which is part of the node, we’ll call it next

7. createEmptyList() Declare a pointer to type node called head n = 0
null

8. isEmptyList(L)
if head == null
return true
else
return false

9. isEmptyList(L)
return head == null

10. access(L, i) declare a pointer temp if i < 0 or i >= n
return null
temp = head
for j = 0; j < i; j++
temp = temp.next
return temp

11. length(L) int count = 0 temp = head while temp != null
count = count + 1
temp = temp.next
return count

12. length(L)
return n

13. searchFor(L, key) int count = 0 temp = head while temp != null
if temp.key = key
return count
count = count + 1
temp = temp.next
return -1

14. insert(L, x)
loop until temp.next == null
then temp.next = x
n = n + 1

15. insert(L, x)
x.next = head
head = x
n = n + 1

16. concat(L1, L2) if head1 == null head1 = head2 else temp = head1
while temp.next != null
temp = temp.next
temp.next = head2
n1 = n1 + n2
return head1

17. remove(L, i) p1.next = p2.next P2.next = null p1 p2 head null p1 p2
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
head
null p1 p2
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
head
null
p1.next = p2.next
P2.next = null

18. inserti(L, i, x) p2.next = p1.next p1.next = p2 p1 p2 head null head
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
head
null
head
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
null p2 p1
p2.next = p1.next
p1.next = p2

19. search-remove p head null NameLast: Smart FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
head
null

20. Doubly Linked List Two pointers per node: next prev tail p head null
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
head
null
null
Two pointers per node:
next
prev

21. Circular Linked List p NameLast: Smart FirstName: Joe StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95
NameLast: Smart
FirstName: Joe
StudentNumber: 8
SSN:
Grade: 95

22. Stacks Stack S = x0 x1 x2 x3 … xn-1 n = # elements
A stack is a list but the nodes are only accessed last-in-first-out (LIFO).
Functions:
createEmptyStack() returns a newly created empty stack
top(S) returns the last node of S
pop(S) returns and removes the last node of S
push(S, x) returns a S with x added as the last element
isEmptyStack(S) returns true if S is empty and false if it is not

23. Homework 2
Describe how to implement a stack using an array (assume it will never have more than 100 elements).
Do the five stack functions.
Describe how to implement a stack using an set of nodes (this stack will have no number of element limit).