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Mon, Oct 27 2008 12:11 PM

Euler problem #6

Find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum. ---- We don't actually need a computer to solve this problem, but why not?   The formula for the sum of the squares of the...
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Thu, May 1 2008 9:40 PM

euler problem #5

What is the smallest number that is evenly divisible by all of the numbers from 1 to 20? ---- To solve this problem easily, we need to remember that the smallest number that is evenly divisible by two numbers is their least common multiple. Armed with...
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Tue, Apr 8 2008 8:35 PM

Euler Problem 4

Find the largest palindrome made from the product of two 3-digit numbers. ----- First, I defined a palindrome recursively: a number is one if its first and last digits are the same, and if the inside is also a palindrome. def palindrome?(digitArr) if...
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Tue, Apr 8 2008 8:07 PM

Euler Problem 3

What is the largest prime factor of the number 600851475143 ? ----- I wrote this piece of disgusting, un-Rubylike Ruby to get the answer by creating a list of a number's prime factors: def factor(composite) i=1 flag=false primefactors =[] while (i...
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Sun, Apr 6 2008 7:55 PM

Project Euler: Problem 2

The problem: Find the sum of all the even-valued terms in the [Fibonacci] sequence which do not exceed four million. Here's my fibonacci function: def fib(limit =nil) f1 = 0 f2 = 1 while (not limit or f2 <= limit) yield f2 f1,f2 = f2, f1+f2 end...
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Sun, Apr 6 2008 1:31 PM

Project Euler in Ruby

I'm taking Bill Wagner up on his Project Euler challenge , but in Ruby. I've secretly wanted to learn Ruby for a long time, and this looks like the perfect chance. So if my code makes your eyes bleed, it's cause I'm a total n00b. Without...
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