I did this one analytically and by brute force simulation, and got the same answer with both methods. It’s in a github gist.

# Tag: Python

# Riddler Express, July 24 2020

Got the Classic from two weeks ago correct, although I hadn’t got the closed-form solution; I needed to spend more time playing with toy examples, but I’m not sure I would have discerned the pattern anyway. It’s neat though.

This week’s Express is not too difficult (*please don’t let me get it wrong!*). The thing that surprised me on thinking about it is that the total number of combinations of shires is only 1024. That’s 2^{10}, since there are 10 shires, each of which can be in or out of any particular subset.

Half of the possibles combinations of shires don’t have enough votes to win, and of those combinations that do, many of them could lose a shire and still win, so they can be ignored as well.

My 33 lines of code will print out an answer in about a millisecond. I assume in Haskell it could be done in about four lines! I should take a look at that language sometime.

# Riddler Classic, July 10 2020

My answer last week seems to be wrong; I thought agreeing with LL would be enough. I will need to look more closely at it.

This week’s Classic is about stacking blocks. At first glance I thought it was Tower of Hanoi, but it’s a little different:

# Riddler Classic, July 3 2020

Got last week’s Express just right, with the right explanation.

This week’s Classic is based on the US flag, but the maths question is this:

[W]hen

Nequals 50,Nis twice a square andN+1 is a centered pentagonal number. After 50, what is the next integerNwith these properties?

# Tidying up ONS data for Pandas

I take an interest in what the UK’s Office for National Statistics puts out, especially around employment and the economy. I’m also learning Jupyter and the Python DS tools, so I’ve taken one of their data series and tidied it up to use in Pandas.