What's a good, generic algorithm for collapsing a set of potentially-overlapping ranges?

Question

I have a method that gets a number of objects of this class

class Range
{
    public T Start;
    public T End;
}

In my case

Answer 1

The idea of collapsing a list just screamed out "reduce" to me. It didn't end up quite as elegant as I had hoped though.

def collapse(output,next_range):
    last_start,last_end = output[-1]
    next_start, next_end = next_range
    if (next_start <= last_end):
        output[-1] = (last_start, max(next_end, last_end))
    else:
        output.append(next_range)
    return output

ranges = [
  (11, 15),
  (3, 9),
  (12, 14),
  (13, 20),
  (1, 5)]

ranges.sort()
result = [ranges.pop(0)]
reduce(collapse, ranges,result)

print result

thanks to yairchu for typing in the data so I could cut and paste it :)