[hide]k=600851475143
temp=k
bigest=1
def test(n)
for i in 2..n**0.5
return false if n%i==0
end
return true
end
tbegin=Time.now
until test(temp)
for i in 2..temp**0.5
if temp%i==0 and test(i)
puts i
bigest = i if i>bigest
temp = temp/i
end
end
end
tend=Time.now
puts "\n",bigest
print tend-tbegin,'s'[/hide]71
839
1471
6857
6857
2.297s>Exit code: 0