At a glance

$ [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 diectory for DigitHoles ... Done

Now:

$ cd DigitHoles/solve/cpp
$ make demo

Output:

Check 0 ... 0m0.328s
Failed
    Input: <42>
    Expected: <1>
    Received: <0>
Check 1 ... 0m0.015s
Failed
    Input: <669>
    Expected: <3>
    Received: <0>
Check 2 ... 0m0.016s
Failed
    Input: <688>
    Expected: <5>
    Received: <0>
Check 3 ... 0m0.015s
Passed
Check 4 ... 0m0.016s
Failed
    Input: <456>
    Expected: <2>
    Received: <0>
Check 5 ... 0m0.016s
Failed
    Input: <789>
    Expected: <3>
    Received: <0>
6 cases checked, 5 failed, 0 errored
Failed cases: 0 1 2 4 5

5/6 test cases failed. That sucks. Now edit the file DigitHoles.cpp with the following content:

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:

Check 0 ... 0m0.141s
Passed
Check 1 ... 0m0.015s
Passed
Check 2 ... 0m0.016s
Passed
Check 3 ... 0m0.015s
Passed
Check 4 ... 0m0.016s
Passed
Check 5 ... 0m0.015s
Passed
6 cases checked, 0 failed, 0 errored

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

$ make sys

Output:

131 cases checked, 0 failed, 0 errored

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

Introduction

Download a TopCoder problem, parse the examples and system tests, then finally generate a basic template for C++, Haskell, and Java. You write the function definition and the generated template will take care of running it against 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, you normally have to paste the solution into TopCoder's online arena where it will be checked for correctness. Even then the online arena only supports C++, Java, and C#.

Installation

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: Most Unix systems have it bundled. Windows users may use MinGW.

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. Now there are a couple things you need to get depending on which language you plan to use to solve problems.

For C++

You are already ready to solve problems using C++. If you want to use make test, you just need to get Boost.

For Haskell

Besides GHC, Cabal is required. But it could have been bundled by your Haskell installer. Now:

$ [sudo] cabal update
$ [sudo] cabal install parsec

HUnit is required if you wish to apply TDD:

$ [sudo] cabal install HUnit

If you don't write tests, there is no need to install HUnit.

For Java

Besides JDK, Apache Ant is required. This should come as no surprise to most Java programmers.

In Java, you use ant instead of make. So:

$ ant demo

Will run against the examples. And:

$ ant sys

Will run against the system tests.

JUnit is required if you wish to run unit tests. Don't use the beta versions. Download one of the stable jar archives and put the jar into Ant's lib dir.

Other languages

At the moment, gettc supports C++, Haskell and Java out of the box. Other languages are provided via plugins.

Tips

Provide your own username/password in ~/.gettc/config.yml if download fails.
Use make sysv (or ant sysv for Java) to display failed cases when challenging the system tests.
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, you can safely delete the whole directory ~/.gettc.

Known Issues

Ambiguous function names

Sometimes the solution method has the same name with a standard library function, such as filter. In this case, you'll have to manually change the function name to something else in the runner and solution files.

String parsing error

TopCoder allows a string to be like "This is" one string", while gettc gets confused with the quote character in between. If your solution fails only under this situation, it's probably correct.

rexdf / gettc