Recently, TopCoder has changed their authentication mechanism to OAuth, and the current code is no longer able to download anything. I have got a solution, but have not quite gotten the time to wrap up. I plan to publish the new bugfix version at some point toward the end of January, 2016.

Download a TopCoder problem, parse the examples and system tests, then finally generate a naive solution for the following languages:

• C++
• Haskell
• Java
• Python 3
• Go
• Ruby
• Javascript

And support for more languages is just around the corner.

You can email me to request support for your favourite language. I will prioritize development on the most requested ones.

You write the function definition and the generated solution will take care of running it against the downloaded input and output files.

TopCoder is a heaven for programmers. Solving algorithmic problems is a great way to embrace the passion for programming. There are problems for all levels. A strong academic background is not required to enjoy it. If you like Project Euler, you will probably love TopCoder.

However, the TopCoder online arena is quite inconvenient and supports only a few languages. Gettc's goal is to make the practice of solving algorithmic problems convenient and fun, and in your desired language.

$ [sudo] gem install gettc
$ gettc 11127

Note that 11127 is the ID that TopCoder gives to the problem named DigitHoles. You can find the ID for any problem if you look at the URL for that problem's statement (you need to have a TopCoder account). Output:

You have given ID = 11127
Downloading problem to raw HTML ... Done
Parsing problem from raw HTML ... Done
Generating problem directory for DigitHoles ... Done

Now:

$ cd DigitHoles/solve/cpp
$ make demo

Output:

[gettc] Compile solver
[gettc] Compile checker
[gettc] Run test cases
Case 0 ... 2ms Failed
    Input: <42>
    Expected: <1>
    Received: <0>
Case 1 ... 1ms Failed
    Input: <669>
    Expected: <3>
    Received: <0>
Case 2 ... 1ms Failed
    Input: <688>
    Expected: <5>
    Received: <0>
Case 3 ... 1ms Passed
Case 4 ... 1ms Failed
    Input: <456>
    Expected: <2>
    Received: <0>
Case 5 ... 1ms Failed
    Input: <789>
    Expected: <3>
    Received: <0>
[gettc] Summary
6 cases checked, 5 failures, 0 errors
Failures: 0, 1, 2, 4, 5
    Total time taken: 7 ms
    Average time taken: 1 ms
    Slowest running case: 2 ms (case 0)

As you can see, the generated solution actually managed to solve 1 test case. Gettc is pretty smart after all. Anyway, you still need to do the hard work. Open the file DigitHoles.cpp in your favourite editor and enter the following content:

class DigitHoles {
public:
    int numHoles(int number) {
        static int holes[] = {1, 0, 0, 0, 1, 0, 1, 0, 2, 1};
        int ret = 0;
        while (number > 0) {
            ret += holes[number % 10];
            number /= 10;
        }
        return ret;
    }
};

And then try again:

$ make demo

You should see:

[gettc] Compile solver
[gettc] Compile checker
[gettc] Run test cases
Case 0 ... 2ms Passed
Case 1 ... 1ms Passed
Case 2 ... 1ms Passed
Case 3 ... 1ms Passed
Case 4 ... 1ms Passed
Case 5 ... 2ms Passed
[gettc] Summary
6 cases checked, 0 failures, 0 errors
    Total time taken: 8 ms
    Average time taken: 1 ms
    Slowest running case: 2 ms (case 0)

Good. We have passed all the example tests. Why not challenge the system tests while we are it?

$ make sys

Output:

[gettc] Compile solver
[gettc] Compile checker
[gettc] Run test cases
[gettc] Summary
131 cases checked, 0 failures, 0 errors
    Total time taken: 233 ms
    Average time taken: 1 ms
    Slowest running case: 7 ms (case 2)

Congratulations! You have solved a TopCoder problem like a boss!

Gettc works on most operating systems, including Linux, Windows, and Mac OS.

The following packages are hard dependencies:

• Ruby: The Ruby installer is recommend for Windows users.
• RubyGems: Many Ruby installations already bundle RubyGems.
• The standard GCC toolset: Specifically, you should be able to run g++ and make from the command line. Windows users may use MinGW or Cygwin.

If you have problems installing on Windows, this may help: https://www.quora.com/How-do-I-install-gettc-for-downloading-TopCoder-problems/answer/Rajneesh-Chauhan

With those in place, we are aready to go:

$ [sudo] gem install gettc

Once that is done, you should be able to run gettc on the command line. The standard procedure is:

$ gettc problem_id
$ cd ProblemName/solve/your_language
$ make

Now there are a couple things you need to get depending on your desired language.

• For C++: You are already ready to solve problems using C++.
• For Haskell: Come here
• For Java: Come here
• For Python: Come here
• For Go: Come here
• For Ruby: Come here
• For Javascript: Come here

• I remember having encountered a problem where gettc failed to download the system tests while it is in fact possible to get the system tests. However, I forgot the problem ID. If you meet such problems, please file an issue so I can fix this.
• There are a few problems that allow multiple answers (such as CorruptedMessage). Gettc cannot deal with this because it can only extract the single answer that TopCoder shows. If you meet such problems, a good guess is to always return the smallest possible value.

• It's good practice to provide your own username/password in ~/.gettc/config.yml.
• You may rm -rf build after you're done solving to save some disk space.
• You can play with the contents of the directory ~/.gettc to, say, remove things you don't want to be generated. If you mess up, run gettc reset.
• You can bring the solutions generated by gettc to another computer to run. Such system doesn't need to have gettc, or even ruby, but it will need the standard gcc toolchain, and of course the compiler for your desired language (if it isn't C++). You will also need to copy ~/.gettc to that system.

This document is for new users. Existing users can find details about updating by reading the change log.