## Project Euler Problems #18, #19, #20 and #67

Problem #18, find the greatest sum of numbers along a path in a triangle of numbers, looks like a standard tree search problem. However, there’s a note at the bottom stating a brute force method won’t work for a harder/bigger version in problem #67. So I decided to skip the exercise of writing the tree […]

## Project Euler Problems #15, #16, #17

Problem #15 Starting in the top left corner in a 20 by 20 grid, how many routes are there to the bottom right corner? I often used this question during interviews and suprisingly, very few candidates were able to make much progress with it. I wasn’t looking for a candidate to code it 100% correctly […]

## Project Euler Problems #12, #13, #14

Problem #12 Find the first triangle number to have over 500 divisors. As I’m progressing through these problems, certain types/sequences of numbers keep popping up. I’ve started a library of functions called eulerLib.py. The first thing I did was add a triangle number generator to my library: def triangleNumber(): num = 1 add = 2 […]

## Project Euler Problems #9, #10, #11

It’s time to get back to discovering how much math and python I’ve forgotten… Problem #9 Find the only Pythagorean triplet (a,b,c where a < b < c and a^2 + b^2 = c^2) where a + b + c = 1000. The first thing I decided to do was figure out some bounds based […]

## Project Euler Problems #6, #7, #8

I took a break from projecteuler to whip up a webOS application before my Tahoe Rim Trail Thru-hike. Upon returning I started skiming some technical books and started playing around with the Facebook Puzzles. In general, starting lots of threads is exciting and gives me the feeling that I am learning a lot; however, I […]

## Project Euler Problems #3 and #5

I got ahead of myself last post and skipped problem 3. Maybe it’s because it wasn’t that interesting: what’s the largest prime factor of 600851475143? Being an odd number meant 2 was not the largest prime factor, and no even numbers are prime so this simple trial division function seemed to work pretty well: def […]

## Project Euler Problem #4

As I work through these projecteuler problems, it’s become apparent that my brain tends towards a particular style of solution. When I know one way to solve a problem, I tend to just implement it, as I want to get to the next one. In the future, I’m going to start trying to find multiple […]

## Project Euler Problem #2

Problem 2 from projecteuler requested the sum of all the even Fibonacci numbers below 4 million. I had seen references to “generators” in some of the Python howtos and after further reading, this seemed like a reasonable place to try them out. def fibGenerator(): fib0 = 0 fib1 = 1 while True: yield fib1 fibNext […]

## projecteuler.net + Python

I’ve started working through the problems at projecteuler, using Python. After playing around with Erlang for a while, I began to dislike the way the programming methodologies were baked into the language. It’s not that I disagreed with them, but sometimes it’s overkill to HAVE to do things via the idioms of assign once and […]