Tisigram 2016 Technical Meeting Tuesday, March 28 th, 2016

Participating (updated March 27 th, WIB) 2

What is it? Writing programs to solve problems in a contest environment Limited time to solve problems (4 hours) Individual contest participation 3 International Olympiad of Informatics 2013 – Brisbane, Australia

Contest format ACM-ICPC problem and scoring format IOI contest format 4 hours of programming One computer for individuals Intro: Topcoder Open 2014 – California, United States

Skills needed Algorithm skills Basic math skills Basic programming skills Speed (Godspeed typing speed helps) Creativity Debugging skills 5 International Olympiad of Informatics 2014 – Taipei, Taiwan

Some prestigious world contests ACM-ICPC (World Finals, National Selection,...) Google Code Jam Topcoder Open Facebook Hacker Cup... 6 Google Code Jam 2013 – London, United Kingdom

Some prestigious national contests Compfest UI Dinamik CS UPI Gemastik Agricode IPB Gemastik 7, 2014 – Yogyakarta, Indonesia

What do you gain? Improve your logical and analytical skills Good point to mention in CV Improve your network of friends Recognition Have fun! Onsite contests also plan excursions! 8 Facebook Hacker Cup 2013 – Facebook HQ, California, United States

Contest system Each problem has a problem setter Writes the problem, generates input test cases and their corresponding correct outputs Your program takes input and generates output in the format specified in the problem Outputs of your program will be compared with the correct outputs 9

Responses from the judge system Pending Accepted (AC) Wrong Answer (WA) Time Limit Exceeded (TLE) Memory Limit Exceeded (MLE) Runtime Error (RE) Compile Error (CE) Output Limit Exceeded (OLE) Forbidden System Call (FSC) 10

A typical problem Problem statement Input and output spec Input and output example Constraints (you don’t check for this! It will be satisfied by the input) Time limit (typically ~10 7 operations under 1s) Memory limit (typically MB at runtime) 11

Example (1) Given two positive integers A and B, print a number representing the sum of A and B. 12

Example (2) Input Format: First line: T ( T ≤ 100 ) indicating the number of test cases Each next T line consists of two positive integers A and B ( 1 ≤ A, B ≤ ) Format Output: For each test case, print the sum of A and B in its own line. 13

Example (3) Input Example Output Example

Example (4) #include int main() { int t, i; scanf( "%d", &t ); for ( i = 0; i < t; i++ ) { int a, b; scanf( "%d %d", &a, &b ); printf( "%d\n", a + b ); } } 15

Example (5) There’s no need to check the constraints (with if blocks) In this case, the constraints is T ≤ 100 and 1 ≤ A, B ≤ Your program should handle those constraints (data types, …) 16

Judging Black-box testing Hidden test cases Input and output examples doesn’t always represents the whole test case Example: gcc source.c -o source./source source.out diff source.out testcase.out 17

Scoring (1) ACM-ICPC standard Each submission will have time penalty Time penalty = duration between contest start time and submission time Each failed submission will be given 20 minutes penalty 18

Scoring (2) # SubmissionVerdictTimeTime PenaltyWrong Penalty Contest started08:00:00 Submission 1Compile Error08:03: Submission 2Wrong Answer08:15: Submission 3Wrong Answer08:22: Submission 4Time Limit Exceeded08:30: Submission 5Accepted08:45:20+46 Penalty calculation Final penalty126 19

Ranking (1) Sorted by number of problems solved (descending) Sorted by total penalty (ascending) Scoreboard will be frozen in last 60 minutes 20

Ranking (2) 21

Common mistakes Outputs that shouldn’t be there Usage of getch() or system("pause") Using void main() or int main() without return 0; exit code Improper formatting 22

Outputs that shouldn’t be there (1) Input Example 10 Output Example 30 23

Outputs that shouldn’t be there (2) #include int main() { int x; printf( "Input Angka: " ); scanf( "%d", &x ); printf( "%d\n", x * 5 ); return 0; } 24

Outputs that shouldn’t be there (3) Detected output Input Angka: 50 Test case output 50 25

Outputs that shouldn’t be there (4) 26

Outputs that shouldn’t be there (5) 27

Usage of getch() or system("pause") getch() and system("pause") made the program not stopping properly (still waiting input from keyboard) when the input is already in EOF state Expected verdict: Time Limit Exceeded 28

Using void main() or not returning 0 (1) System must get 0 exit code from program to determine that no runtime error get through int main() {... return 0; } 29

Using void main() or not returning 0 (2) 30 Answer of Andre Tisigram 2015 testing session

Improper formatting All output should be ended with a newline 31 Answer of Maulana Tisigram 2015 testing session

Questions? About problems, test cases, verdicts, … while on contest: Clarification tab on upper menu Judges will be online when contest is running Outside contest: 32

Clarifications Ask problem-related questions “Clear enough” “Judges have no comment” … Receive important announcement from judges Delayed competitions, time extensions … 33

Training System March 21 th – April 3 rd “Sesi Latihan Tisigram 2016” Username: NIM | Password: reverse(NIM) 34

Contest Simulation Friday, April 1 st, 2016, WIB - “Simulasi Kontes 2 Tisigram 2016” Username: NIM | Password: reverse(NIM) 35