Problem A common security method used for online banking is to ask the user for three random characters from a passcode. For example, if the passcode was 531278, they may ask for the 2nd, 3rd, and 5th characters; the expected reply would be: 317. The text file, keylog.txt, contains fifty successful login attempts. Given that [...]

Problem Some positive integers n have the property that the sum [ n + reverse(n) ] consists entirely of odd (decimal) digits. For instance, 36 + 63 = 99 and 409 + 904 = 1313. We will call such numbersreversible; so 36, 63, 409, and 904 are reversible. Leading zeroes are not allowed in either [...]

Problem The number 145 is well known for the property that the sum of the factorial of its digits is equal to 145: 1! + 4! + 5! = 1 + 24 + 120 = 145 Perhaps less well known is 169, in that it produces the longest chain of numbers that link back to [...]

The first of this series covered our general aims how we’d be structuring the project. This post will cover how we get the data into RavenDB. First we need to download the data. I got it obtained the data from this site, you need to click the “téléchanger la base” link under “Coordonnées géographiques des villes Françaises” here is the direct link. It’s not the best data source in the world, but it’s the best freely available one that I’ve found. Once you’ve unzipped the zip and converted it CSV the loadi[...]

So Stack Overflow Dev Days has been cancelled. Obviously it’s a big disappointment to everyone involved, I thought the line up for the London event was great and I was looking forward to attending the conference as much as I was looking forward to speaking at it. If it’s any compensation you can see me do this talk at skill matter as one of their in the brain sessions: The Combinator Approach to Programming Domain Specific Languages with F# Using a “combinator” approach to create internal Domain Specifi[...]