Puzzles

Lately I've been using Pharo to solve Project Euler puzzles. Several things I've found:

• Getting an idea to start is helpful. Resources like the Encyclopedia of Integer Sequences are a good start.
• Early problems simply deal with integer overflow, this isn't a problem in Smalltalk since SmallIntegers are automatically converted into LargeIntegers.
• More complex code can be profiled by adding them to a block and using timeProfile:

  [ 4700 naturalSummarySizeModulo: 1000000 ] timeProfile.

  This generates a diagram like:

  
  One can find where the majority of the time is being spent.
• If the code runs for a long while, one technique is to place it in a block and use fork to put it in the background. If a large amount of space is used in the background process, it isn't a good idea to save the image (it may hang, save the code to a repository instead). It also isn't such a good idea to increase the process priority.

  For a running process that is forked into the background, it is possible to bring up the process browser and profile the process:

  
  More details are in the profiling chapter of Deep into Pharo.
• Several of the Project Euler puzzles involve downloading a list of numbers and evaluating them. This can be done by something similar to:

  (ZnClient new
  	beOneShot;
  	get: 'https://projecteuler.net/project/resources/p079_keylog.txt';
  	contents) substrings collect: [ :e | e asNumber ]