Tutorial 1 C Programming

1
Tutorial 5Stack Queue, Midtest
2
Stack

• Last In First Out (LIFO)
• Stack implemented using Array with top pointer
• http//www2.latech.edu/box/ds/Stack/Stack.html
• Stack implemented using Single Link List with
  head pointer
• Probably the best implementation to date?
• http//www.cosc.canterbury.ac.nz/people/mukundan/d
  sal/LinkListAppl.html

TOP
3
Queue

• First In First Out (FIFO)
• Queue implemented as Circular Array
• http//maven.smith.edu/streinu/Teaching/Courses/1
  12/Applets/Queue/myApplet.html
• Queue implemented as Single Link List with Tail
  Pointer
• Head pointer (easy for insert/delete) for dequeue
• Tail pointer (only easy for insert) for enqueue
• This is because of the pointer directions
• Probably the best implementation to date?

FRONT
BACK
4
Student Presentation

• T3 Main Backup
• Cai Jingfang Chng Jiajie, Colin Tan
• Li Huan Nur Liyana Bte Roslie
• Zhang Jianfei Tan Kar Ann
• Tanvir Islam Jessica Chin Zet Sze
• T4 Main Backup
• Choy Qian Ning, J Liew Hui Sun
• Goh Khoon Hiang Li Yawen
• Hanyenkno Afi Tan Peck Luan
• Ng Xue Lin Sherilyn Wong Suet Teng, Melissa

• T5 Main Backup
• Joyeeta Biswas Ong Kian An
• Teo Sim Yee Stephanie Tan Yan Hao
• Wu Shujun Wang Ruohan
• Liu Na Zheng Yang
• T6 Main Backup
• Zhang Chao Wang Shuling
• Chua Yu Tong Laura Rasheilla Bte Rajah
• Koh Yi Ting Brenda Low Wei Chen Gerard J
• Siddhartha Gan Zhi Wei James

Rule Student in Main column has priority to
answer the assigned question If the student
sick/disappear/absent/cannot solve, etc2 the
backup will take over. If both students are
attending the session,I will create variants of
the question for the backup students.
5
Question 1 (Applications)

• Show us 7 applications of Stacks
• Show us 7 applications of Queues
• Be creative!

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Question 2 (Stack Reorder)

• Get algorithm to reorder items using one stack!
• Requires thinking on Stack operations push, pop,
  top/seek
• Derive patterns!
• Target Sequence 1 1, 2, 3, 5, 4
• Target Sequence 2 2, 1, 4, 3, 5
• Target Sequence 3 5, 2, 4, 3, 1
• Target Sequence 4 1, 4, 3, 2, 5

Only Target Sequence 3 is impossible. See
StackTest.java for details
7
Question 3 (Stack for Sorting)

• Find algorithm to sort items using two stacks!
• Requires thinking on Stack operations push, pop,
  top/seek
• Hint try sorting these simple numbers using two
  stacks
• 7, 5 ? 5, 7
• 1, 5, 3 ? 1, 3, 5
• 4, 3, 2, 1 ? 1, 2, 3, 4
• Derive patterns and write your algorithm!
• Hint During the sorting process, one stack will
  have numbers in ascending order and the other in
  descending order.
• See StackSort.java for details

8
Question 4 (Queue)

• What if Queue ADT is implemented using
  TailedLinkedListbut in different way!
• Think about the pros and cons of this strategy!
• The ADT Queue dequeue operation is performed by
  delete head and ADT Queue enqueue operation
  is performed by insert from tail in
  TailedLinkedList.
• Modified operations
• Enqueue insert from head ? straightforward
• Dequeue delete from tail ? hard, because
  adjusting tail pointer is difficult!
• No pro, this modified operations are bad!
• If you are presented with this kind of question
  during exam, do not hesitate to answer there is
  no pro rather than leaving your answer blank!
• If you insist, you can say that this modified
  operations can easily tell you what object is
  the 2nd last inserted object

9
Student Presentation for Tut 6

• Check your email!
• If I send you an email, it means that you are
  assigned to do next weeks questions

10
Midterm Test Tips

• Priority
• Java Revisit low
• ADT Likely embedded in Linked List/Stack/Queue
  question
• Linked List we spend two weeks here, most likely
  this appear as the only short question during
  midterm test
• Stack and Queue definitely appear
• Try
• Mixing and matching various data structure
  implementations variant of linked list,
  implementing stacks or queues using funny data
  structures, etc