Even though I saw through their tricks at every step along the way, I am now a customer and proud of it. It is worthwhile to look at what they did, because these are simple things that you can do to improve your software business.
The difference between two sequences A and B can be compactly stored using COPY/INSERT operations. The greedy algorithm for finding these operations relies on an efficient way of finding the longest matching part of A of any given position in B. This article describes how to use a suffix array to find the optimal sequence of operations in time proportional to the length of the input sequences. As a preprocessing step, we find and store the longest match in A for every position in B in two passes over the suffix array.
A/B testing is used far too often, for something that performs so badly. It is defective by design: Segment users into two groups. Show the A group the old, tried and true stuff. Show the B group the new whiz-bang design with the bigger buttons and slightly different copy. After a while, take a look at the stats and figure out which group presses the button more often. Sounds good, right? The problem is staring you in the face. It is the same dilemma faced by researchers administering drug studies. During drug trials, you can only give half the patients the life saving treatment. The others get sugar water. If the treatment works, group B lost out. This sacrifice is made to get good data. But it doesn't have to be this way.
Today, we will examine four different methods of performing the same task asynchronously, in node.js.
After many months, your software sale is complete! You've got a purchase order, sent the invoice, delivered the software. You're already handling some support issues from users at BigCorp. Then BANG! Martha from Procurement emails back, as a favour, just to let you know that BigCorp has not received your W8 form with a valid tax id, and therefore will be withholding 30% of the purchase price of your multi-thousand dollar product for taxes.