Project Euler again, this time Python. The problem is to sort a list of 5000 names alphabetically then give them a value. For example “COLIN” is 3 + 15 + 12 + 9 + 14 = 53 and is the 938th item – so its value is 49714 (53*938).

### Find the sum of amicable numbers under 10000

Project Euler problem 21 is to find the sum of all amicable numbers under 10000. An amicable number is:

Let be the sum of proper divisors of then and if then and are amicable numbers.

Continue reading “Find the sum of amicable numbers under 10000”

### Sum a list of 50 digit numbers

Problem 13 is summing a list of fifty digit numbers. I used the gmp library and R to solve in 2 lines:

library(gmp) print(substring((sum(as.bigz(readLines("euler13.txt")))), 0, 10))

Not much more to say really. I forgot the problem asks for the first 10 digits, so my first answer was wrong.

### First triangular number with 500 divisors

OK so today I’m trying problem 12 – find the first triangular number with over 500 divisors. This is the first Project Euler problem I’ve really struggled to find a solution *in a reasonable amount of time*. Continue reading “First triangular number with 500 divisors”

### Product of 4 consecutive numbers

I’m beginning to like R. You can capture table data from a connection (a generalised file), one of which is the clipboard, to a data frame.

problem.matrix <- as.matrix(read.table("clipboard",sep=" "))

### Project Euler, Visual Studio and playing with Python

I got Visual Studio 2017 through Microsoft’s Dreamspark promotion and thought I’d give it a try. I haven’t done a lot of development under Windows because its only on my laptop and my Linux desktop has 12 Gb RAM.

Continue reading “Project Euler, Visual Studio and playing with Python”

### Simple Arch Linux Installation

This is a quick post to remind myself of the stuff I do when re-installing Arch. Continue reading “Simple Arch Linux Installation”

### Asus X541S

My wife’s laptop is an Asus X541SA – a fairly generic and inexpensive workhorse. With a Quad-Core N3710, 4Gb of RAM and a 1TB HDD. Unfortunately its ridiculously slow. Opening, switching and closing applications leaves time to make a cup of tea and clicking save in Word is likely to see a “(not responding)” caption in the title bar.

A quick look in task manager shows the HDD is perpetually at 100%. Having already tried a clean install of Windows 10, I figured an SSD might help. I got this 120 Gb SanDisk SSD, having used them before with good results.

What a difference it makes, the laptop is not only usable but responsive. While I doubt it would handle many games it can at least cope with Office and Firefox, which it couldn’t before.

### Graduation Ceremony

I attended the University’s Graduation Ceremony at Ely Cathedral yesterday. If theres one thing that the UK loves, it’s a ceremony.

It was very well organised and planned. Free parking wth a shuttle bus to the Cathedral, clear direction to registration, robing and photography. There were a lot of nervous graduates but there needn’t have been. Ushers sent each row of graduates up along the side, where out of sight lists were checked and someone straightened our robes.

I think there’s probably more value in these things for family than for the graduates themselves but I enjoyed the day.

Not sure where to go from here. I enjoy studying – masters seems logical but I don’t have the interest I once did in Computing. I’ve looked at the Open Masters but would need to focus on science and the choice seems a little narrow. I guess I’ll figure it out.

### Flashing Nexus 9 factory image

This tablet was super fast when I got it but now it lags and drives me nuts. I’d seen someone post on Reddit that flashing the factory image helped so I gave it a go.

Factory images are available here along with good, clear instructions. One caveat, Arch needs super user for fastboot otherwise you get “< Waiting for device >”. For the same reason run flash-all.sh with sudo too.

As to whether or not it helped, it is hard to say but I feel it has. How do you measure something that is entirely subjective?

**Edit. **Its been a few days now and** **it *is* faster. Much faster and without lag. I’m unclear why though. I’m not completely familiar with Android’s architecture but wonder if it’s a combination of multiple updates being applied (this was I think Android 5.0 when bought) and accumulated futz.