Snippet

project_euler/25.rb

Code:

# Project Euler Problem 25: 1000-digit Fibonacci Number

# https://projecteuler.net/problem=25

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

def solve(n)
    a, b, i = 1, 1, 1
    i, a, b = i + 1, b, a + b while a.to_s.size < n
    return i
end

puts solve(3)
puts solve(1000)

Output:

12
4782