Liam Goodacre

Humble Mumble: Introducing Humble Indie Bundle V!

Haskell: Project Euler - Problem 1 Extension

My solution to problem 1 was a function that accepted two multiplier values and a limit. I decided to write an extension that allowed a list of multiplier values. The following is the result (and is still pretty short!):

--  Function Solution
euler1x l = sum . foldl (\x y->union x [y,y+y..l-1]) []

--  Example:
euler1x 1000 [3,5]

Yay Haskell!

Haskell: Project Euler - Problem 2

Problem 2: By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.

--  Original approach
euler2 m = let fib x y = x:fib y (x+y) in
  sum $ takeWhile (< m) $ filter even $ fib 1 1

--  Secondary approach (not generating odd values)
euler2b m = let gen x y = (x+y):gen (x + 2*y) (2*x + 3*y) in
  sum $ takeWhile (< m) $ gen 1 1

Haskell: Project Euler - Problem 1

I’ve decided to go through Project Euler in an attempt to learn Haskell. (Yay Haskell*)

I’m also setting out to attempt interesting, short, or efficient approaches to the problems - depending on my mood and interest.

Problem: Add all the natural numbers below one thousand that are multiples of 3 or 5.

--  Include the union function
import Data.List (union)

--  Function for computation
euler1 a b l = sum $ union [a,a+a..l-1] [b,b+b..l-1]

--  Application example
euler1 3 5 1000
--  result => 233168

*Yay Haskell!

Wtf, in JavaScript, the numbers: 9999999999999999, 10000000000000000, and 10000000000000001, are exactly equal to 10000000000000000.

10000000000000000 - 1 === 10000000000000000

10000000000000000 - 2 !== 10000000000000000

10000000000000000 - 1 - 1 === 10000000000000000

10000000000000000 + 2 - 1 === 10000000000000000

As are the negations:

-9999999999999999 === -10000000000000001

Say what?

Angular Javascript