Problem 3 (written in Ruby)
# 2で割り切れないことは自明である
n = 600851475143
factors = []
i = 0
while true do
devided = false
3.step(n, 2) do |i|
if n % i == 0 then
factors << i
n = n / i
devided = true
break
end
end
break if not devided
endfactors.each{|n|puts n}
Problem:
http://odz.sakura.ne.jp/projecteuler/index.php?Problem%203