HKOI 2004

1
HKOI 2004

• Briefing for Finalists

2
Todays Schedule

• HKOI Background Goals
• About the Final Event
• Q A Session
• Useful Techniques Open Problem
• Q A Session
• Things to Note
• Q A Session

3
HKOI Background Goals

• Aims
• Select potential candidates for inter- and intra-
  national competitions

4
HKOI Background Goals

• Inter- and Intra- national Competitions
• AGAMES (SEARCC in the past)
• NOI (National Olympiad in Informatics)
• IOI (International Olympiad in Informatics)

5
HKOI Background Goals

• Benefits of Participating in HKOI
• Improve your problem solving skill
• Prizes
• Chances to represent Hong Kong in inter- and
  intra- national competitions
• Fun with programming and making new friends

6
About the Final Event

• Number of Questions 5
• 100-mark Question x 4 400 marks
• 50-mark Question x 1 50 marks
• Total 450 marks
• Duration 3 hours

7
About the Final Event

• Equipment
• Desktop computer (with similar hardware
  software configurations)
• NO other electronic device is allowed
• Your own stationery

8
About the Final Event

• Equipment (Desktop Computer)
• Running Windows
• You can use ANY software provided
• You are NOT allowed to install any software
• All temporary files should be put in C\HKOI

9
About the Final Event

• Programming Languages
• PASCAL, C or C
• Programming Environment/Tools
• Turbo PASCAL 7.0 (TP 7.0)
• Turbo PASCAL for Windows 1.5 (TPW 1.5)
• GNU GCC 3.x (MinGW version)
• Format Checkers

10
About the Final Event

• Solution Submission
• 2 diskettes will be given
• Save SOURCES and EXECUTABLES on BOTH diskettes
• Save under the root directory (A\) of the
  diskettes

11
About the Final Event

• Judging
• One of the 2 diskettes will be chosen randomly
• ONLY RESULTS of the executables will be marked
• 5-30 test cases for each question
• Different test cases may carry different marks
• Scores will be given for each correct test case

12
About the Final Event

• Definition of Correct Test Case
• EXACT Output Format
• Doing less gets NO marks
• e.g. Missing separator
• Doing more gets NO marks
• e.g. ANY Screen Output, ANY trailing spaces
• Correct Answer

13
About the Final Event

• Ranking
• ONLY results in the Final Event will be counted
• About top 30 candidates from each group will be
  chosen as potential trainees

14
About the Final Event

• Q A in the Final Event
• Normally we will answer YES, NO or NO COMMENT
  only
• Both questions and answers will be announced to
  all candidates

15
About the Final Event

• Q A Session

16
Useful Techniques Open Problem

• File I/O in PASCAL
• Text
• Assign
• Reset
• Rewrite
• Read/Readln
• Write/Writeln
• Close

17
Useful Techniques Open Problem

• File I/O in C
• FILE
• fopen
• fscanf
• fprintf
• fclose

18
Useful Techniques Open Problem

• File I/O in C
• ifstream
• ofstream
• ifstreamoperator gtgt
• ofstreamoperator ltlt
• endl

19
Useful Techniques Open Problem

• Open Question
• Errors scoring zero marks
• Trailing Space(s)
• Unclosed File
• Outputting to Screen
• Reading from Keyboard
• Reading from Files not in Current Directory
• Non-silent Executable
• Extra Line(s)
• Nonzero return value

20
Useful Techniques Open Problem

• Open Question
• Errors scoring some marks
• Incomplete Solution

21
Useful Techniques Open Problem

• Some Simple Algorithms/Skills
• Data Processing
• Mainly in Junior
• Basic in Senior
• Simple Mathematics

22
Useful Techniques Open Problem

• Searching
• Linear Search
• Breadth First Search
• Depth First Search

23
Useful Techniques Open Problem

• Optimization
• Exhaustion
• Brute force, search all cases and compare
• Dynamic Programming

24
Useful Techniques Open Problem

• Q A Session

25
Things to Note

• Before the Competition
• Well Prepared
• Open question
• File I/O in PASCAL, C or C
• Basic algorithms

26
Things to Note

• During the Competition
• Listen and follow the instructions

27
Things to Note

• At the Beginning
• Check the equipment carefully
• e.g. diskettes, temporary directory
• Check the programming environment carefully
• e.g. compiling method, output path of executable
• Read ALL problem descriptions
• Do the easiest one first
• Raise questions

28
Things to Note

• In the Middle
• For Easy Problems
• Make sure your program works for all input
• For Hard Problems
• Do as much as you can
• There will be a wide range of difficulty among
  test cases
• Scores will be given for each correct test case

29
Things to Note

• In the Middle
• Dont do more
• No need to validate input
• No output to screen
• No extra output, etc
• Dont do less
• NO partial score for test cases
• Save your programs frequently

30
Things to Note

• Near the End
• No need to clean up the temporary directory
• Remember to store the SOURCES and EXECUTABLES on
  BOTH diskettes
• Check the filenames
• Sources
• Executables
• Input Output Files

31
Q A Session

• Reference
• Software Competition Reference Materials
• http//www.hkace.org.hk/hkoi/hkoi_ref.htm
• Open Question
• http//www.hkoi.org.hk/
• Un-official Newsgroup
• news//hkoi.com/hkoi