09 May 09 Project Euler: Problem 25 in Ruby

Skipping around a bit, I saw that #25 looked pretty easy. It was. I saw in the forums that someone had used binary search and a calculator which I thought was pretty clever, but mine was just brute force.

Problem #25

What is the first term in the Fibonacci sequence to contain 1000 digits?

Solution

max  = 10 ** 999
a, b, i = 1, 1, 2

while b < max
  i += 1
  a, b = b, b + a
end

puts i

Tags: project euler, ruby

Filed in code

Reader's Comments

1. Project Euler: Problem 13 in Ruby » Code Musings and Such | 10 May 2009 10:04 pm

   [...] ran this and #25 through ruby 1.8.6 and 1.9.1 and was suprised to see that it ran much slower in the newer version. [...]

2. Misti Cooper | 02 Feb 2010 1:37 am

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