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How may people can be on a team?


What programming languages will be used for the contest?

C, C++, Java, Python 2, Python 3 and Kotlin.

What judging system will be used?

Kattis. Your can create a free account and try out Kattis at Note that the actual contest will use different login credentials which will be provided at your contest site.

What can we bring?

Books, printouts, scratch paper. Basically, nothing electronic, or electronically readable media. This means possesion of cell phones, calculators, tablets, flash drives etc. is not allowed during the contest.

Note you are allowed online access to the following reference sites:,, and

What do you provide?

Site specific, but your team will have a single workstation, scratch papers, printers, and have access to a classroom (or part of one) or similar place to work in relative privacy.

What problems should we do first?

Since the time penalty for each correct problem is from the start of the contest, you should get the easiest problems done first. Note that determining which problems are easy is part of the contest! Seeing how other teams are progressing on the problems can help your team determine this.

What do we submit?

A single source file which (if correct) solves the problem; with the following conventions:

C++ Example

C++ extension is .cpp

// count.cpp
#include <iostream>
#include <string>

using namespace std;

int main(int argc, char *argv[])
    string line;
    int lines=0;
    while (getline(cin,line)) {
    cout << lines << endl;
    return 0;

Build, Run and Test

$ g++ -g -O2 -std=gnu++11 -static -o count count.cpp -lm
$ cat | ./count | diff - count.out

C Example

C extension is .c

#include <stdio.h>
#include <string>

#define MAX_LINE_LENGTH 100000
char linebuffer[MAX_LINE_LENGTH+1];

int main()
    int lines=0;
    while (fgets(linebuffer,MAX_LINE_LENGTH+1,stdin)!=0) {
    return 0;

Build, Run and Test

$ gcc -g -O2 -std=gnu99 -static -o count count.c -lm
$ cat | ./count | diff - count.out

Java Example

Java extension is .java and public class of base name with no (default) package.

public class count {
    public static void main(String[] args)
        throws Exception {
        String line;
        int lines=0;
        java.util.Scanner in=
            new java.util.Scanner(;
        while (in.hasNextLine()) {

Build, Run and Test

$ javac -encoding UTF-8 -sourcepath . -d .
$ cat | java -Xss64m | count | diff - count.out

Python 2 Example

Python 2 extension is .py

#!/usr/bin/env python2
import sys
print sum(1 for line in sys.stdin)

Run and Test

$ cat | python2 | diff - count.out

Python 3 Example

Python 3 extension is .py and shebang (#!) of /usr/bin/env python3.

import sys
print(sum(1 for line in sys.stdin))

Run and Test

$ cat | python3 | diff - count.out

The judging system actually lets you turn in any source file for any problem, but sticking to this convention keeps you from turning a solution to the wrong problem.

How do we edit/compile/run our code?

Again site specific. Assuming you are using a unix-like operating system the least-common-denominator editor is probably pico, which you can run by typing

$ pico source-file-name

at the command prompt, although your site probably supports an IDE like elipse or netbeans; or both. Look at the previous question to see build and run examples.

How do we test our code?

Here’s a test checklist:

How do we debug our code?

More site specific. gdb is the command line debugger for C and C++ programs, and you might have ddd, which is a gui-interface for this. Read the banners and h is for help. The installed IDE’s should support debugging; and otherwise think about print statements with an if (debug) mask.

In the judge setting, your program will be run with no arguments and the output of STDERR is ignored. You can use these mechanisms to report debugging information without changing how it behaves during judgement (although creating lots of debugging output that is ignored can hurt how long it takes your program to run).

How do we submit a problem/clarification?

We will be using Kattis for our judge environment this year. You should have gotten an email about creating a kattis account from your team registration, and you can try the warmup at before the contest at

How are teams ranked?

Teams are first ranked by number of correct solutions: the more problems which are solved by a team, the higher their rank.

Teams that have finished the same number of problems are then ranked by fewest penalty points: the fewer points, the higher the rank. The penalty points accrued for your team is the sum of:

Example: The contest starts at 10:00 am; Team Zorbo, turns in problem 1 correctly at 10:43, makes two incorrect submissions of problem 2 before submitting a correct solution at 12:35, and makes 3 incorrect submissions for problem 3 without ever turning in a correct solution. The Zorbos would have 225 penalty points broken down in the following table:

Problem Submission Penalty Time Penalty Total
1 0*20 = 0 0:43 = 43 43
2 2*20 = 40 2:25 = 145 185
total 2*20 = 40 3:08 = 188 225

Note that there is no penalty accrued for problem 3, since it was never submitted correctly

Incidentally, the last tie-breaker rule is the time of the last correct submission.