I love Google Code Jam. I love solving problems, and Code Jam problems are fun! I also like competing, and since I wasn’t blessed with good athleticism or a desire to have good athleticism, Code Jam gives me a chance to compete using skills I am passionate about.

I like solving Code Jam problems in python. Python is very expressive, clear, and concise. If you worry about speed, 99% of the problems are solvable in python, but a language like C (being 1-2 orders of magnitude faster) will cover up more mistakes than python. Python has many useful objects in its standard library and language definition that make doing complex tasks easy. I will probably do a post about a bunch of those sometime, but for now, I’d like to introduce pycodejam.

Every time I write a solution to a Code Jam problem, I have to rewrite code to feed in the input and write the output. I make mistakes a lot of the time and that costs me precious minutes during the competition. A while ago I wrote some basic functions and started copying them between every solution I wrote, but the code was ugly and didn’t contribute to the idea of solving the problem.

So I wrote a small library to help run code jam problems. In some problems, you could only need as little as 3 lines of code to run the problem. Here’s an example to motivate your interest:

Suppose the problem was to take 3 lines of integers, element-summing the first two as if they were vectors and comparing those values to the third, then the program should output ‘Case #n: Yes’ if those vectors match, and ‘Case #n: No’ if they don’t.

def solve(v1, v2, vc):
  if all([x+y == z for x, y, z in zip(v1, v2, vc)]):
    return 'Yes'
    return 'No'

if __name__ == "__main__":
  from codejam import CodeJam, parsers
  CodeJam(parsers.ints, solve).main()

The pycodejam parsers know how to interpret basic code jam input files. The simple parsers provided in the codejam.parsers module likes ints, floats, words, and lines assume there are a constant number of lines per case input. Once they figure that out, its a simple matter to interpret each line as an array of integers (as the ints parser does). For more complicated input files, such as those with variable lines per case, there’s a nice decorator called custom_iter_parser located in the parsers module.

pycodejam is available on pypi and can be installed with pip. Checkout the github repository for more details. I’ll be adding some api documentation shortly.