Adjacent number algorithm grouper

Question

By which I mean this:

Given the input set of numbers:

1,2,3,4,5 becomes \"1-5\".

1,2,3,5,7,9,10,11,12,14 becomes \"1-3, 5, 7, 9-12, 14\"

This is

Answer 1

I'm a bit late to the party, but anyway, here is my version using Linq:

public static string[] FormatInts(IEnumerable ints)
{
 var intGroups = ints
  .OrderBy(i => i)
  .Aggregate(new List>(), (acc, i) =>
  {
   if (acc.Count > 0 && acc.Last().Last() == i - 1) acc.Last().Add(i);
   else acc.Add(new List { i });

   return acc;
  });

 return intGroups
  .Select(g => g.First().ToString() + (g.Count == 1 ? "" : "-" + g.Last().ToString()))
  .ToArray();
}