This post will touch on two subjects that I already talked about, Amara's Law and creativity thrives in structure. I will reiterate Amara's Law here though:
We tend to overestimate the effect of a technology in the short run and underestimate the effect in the long run.
So in the previous post I showed how to use the pattern of Suppliers and Consumers to structure any kind of input and output of data and structuring the processing. Well for bonus points we are going to make something fancy, a Chain. A Chain is nothing more than the series of steps that starts with one action and the result of that action will be the input for the next action and so on all the way till the end. Let us make one.
This first part will deal with setting up the problem and the first initial code.
The problem to solve is to find the first x amount of Narcissistic Numbers . What they are is easy to explain. The process by which to identify if a number is narcissistic is by following these steps:
The first improvement we will make is to move away from int to string to int conversion in the previous code and implement integer only operations. We can do this by using the modulo and floor integer division.
A small mini optimization is to move the call to len out as the length of the number does not change.
The next thing we can optimize is the fact that the result of the powers calculation does not change during the same length of the numbers. In order words, 3 ** 3 does not change for the numbers 123, 345, 543 and any other number containing a 3 in the range of 100 – 999.
The next mini optimization we can do is to bail out earlier because when summing the number and we overshoot the original then we can stop immediately. For example 9 ** 6 is a big number and so with bigger numbers it makes sense to bail out earlier.
So for the smart people out there they might have already figured out that the result for 153 is the same as for 135,315,351,513 and 531. This means that we can calculate the result for all of those once and just check if the result of that calculation is in that list. Which is the case for the number 153.
This post is about a thin line between a helpful utility and full on magic show.
This post will have a lot of code and Java at that, so warning has been given. I happened on this little gem in the Java standard library that allows you to make a nice asynchronous model of execution with some guidance. Only the thing missing from the documentation of the Java standard library, in contrast to the one provided by Python, are examples on how to use this one. There is an example on the main page of the package. So this is my attempt at creating the implementation of these interfaces and hooking them up together based on the wordings in the documentation.