The answer in Ruby (so far)

a = [1,2,3,5,7,8,9,10,12,13,19,200,900,901,902,903,904,905,1000]
l = a[0]
f = a[0]
z = a.length
i = 0
s = “”
until i == z
if (a[i]+1 == a[i+1])
l = a[i+1]
end
if (a[i]+1 != a[i+1])
if f == l
s = s+”#{f}”
if [...]

Code Golf – Home On The Range

Home On The Range
It’s as simple as “1 2 3 5 6 8″ => “1-3, 5-6, 8.”
The Problem
It’s difficult to spot what’s missing in a long list of numbers if they are just listed one after the other. You can make it easier by organising the numbers into ranges, and that’s exactly what you’re going [...]