COMP9024

COMP9024 Assignment One
Objectives
• Give you experience with doubly linked lists
• Understand how to solve set union, set intersection and longest sublist problems
• Give you practice with time complexity analysis
• Give you further practice with C and data structures
Admin
Marks 12 marks. Marking is based on the correctness and efficiency of your code. Your
code must be well commented.
Group? This assignment is completed individually
Due Time 10:00 pm Sunday, March 14, 2021.
Late Submissions Late submissions will not be accepted!
Aims
In this assignment, you will implement a set of functions based on the doubly linked list
defined in MyDLList.c.
The functions you need to implement are shown as follows:

1. DLList CreateDLListFromFileDlist(const char filename). This function creates a
   doubly linked list of integers by reading all integers from a text file named filename,
   and returns a pointer to the doubly linked list where each node stores one integer.
   Assume that adjacent integers in the file filename and the standard input are
   separated by one or more white space characters or a new line character.
   If filename is “stdin”, CreateDLListFromFileDlist (“stdin”) creates a doubly linked list
   by reading all integers from the standard input and the word end denotes the end of
   input.
   This function must check for invalid input. In case of invalid input, it prints an error
   message “Invalid input!” and returns NULL. (2 marks)
2. void printDLList(DLList *u ). This function prints all the elements (integers) of a doubly
   linked list pointed by u in the order from the first node to the last node in the list on
   the standard output, one element per line. (1 mark)
3. DLList cloneList(DLList u). This function creates an identical copy of a doubly linked
   list u and returns a pointer to the list cloned. (1 mark)
4. DLList longestSublist(DLList u). This function returns a doubly linked list that is the
   longest sublist of u. The longest sublist v of a list u is defined as follows:
   a. The greatest common divisor of all the elements (integers) of v is not 1 (we
   consider positive divisors only).
   b. No other sublist of u contains more elements than v.
   Assume that all the integers in the list pointed by u are distinct.
   Consider a list u = {2, -6, 8, 15, 11,23, 20}. The longest sublist v of u is {2, -6, 8, 20},
   and the greatest common divisor of all the elements of v is 2.
   Note that the longest sublist of a list may not be unique. Consider a list u = {2, 6, 4, 3,
   9}. There are two longest sublists: v1={2, 6, 4} and v2={6, 3, 9}. If there are multiple
   longest sublists, this function returns any one of them.
   When analysing the time complexity of your algorithm, you may assume that the
   maximum integer of the input list is a constant. Under this assumption, it takes
   constant time O(1) to check if two integers are mutually prime (i.e., their only divisor
   is 1). (3 marks)
5. DLList setUnion(DLList u, DLList *v). This function computes the union of the two
   sets of integers that are stored in the doubly linked lists pointed by u and v,
   respectively, and returns a pointer to the doubly linked list that stores the union. Each
   element (int) of a set is stored in a node of the corresponding doubly linked list.
   Given two sets A and B, the union of A and B is a set that contains all the distinct
   element of A and B. For example, assuming that A = {2, 8, 5, 7} and B = {5, 9, 6, 7}, A
   ꓴ B = {2, 8, 5, 7, 9, 6}. Note that in a set, all the integers are not necessarily sorted.
   (2 marks)
6. DLList setIntersection(DLList u, DLList *v). This function computes the intersection
   of the two sets of integers that are stored in the doubly linked lists pointed by u and
   v, respectively, and returns a pointer to the doubly linked list that stores the
   intersection. Each element (int) of a set is stored in a node of the corresponding
   doubly linked list. (2 marks)
   For simplicity, you may assume that all the elements of each input set are distinct
   for both set union and set intersection. Therefore, you do not need to check if a set
   contains duplicates.
   Given two sets A and B, the intersection of A and B is a set that contains all the
   elements of A that are also in B. For example, assuming that A = {2, 8, 5, 7} and B = {5,
   9, 6, 7}, A ꓵ B = {5, 7}.
7. void freeDLList(DLList *u). This function frees the space occupied by all the nodes of
   the doubly linked list pointed by u. (1 marks)
   Time complexity analysis: For each function, you need to analyze its time complexity in terms
   of big-O notation and put your analysis as comments immediately before the code of the
   function. You may assume that each built-in I/O function such as printf(), malloc() and free(),
   takes O(1) time.
   How to submit your code?
8. Go to the assignment one page
9. Click on Assignment Specfication
10. Click on Make Submission
11. Submit your MyDLList.c file that contains all the code.