Code golf: combining multiple sorted lists into a single sorted list

Question

Implement an algorithm to merge an arbitrary number of sorted lists into one sorted list. The aim is to create the smallest working programme, in whatever language you like.

Answer 1

I don't think you can get much better than @Sykora's response, here, for Python.

Changed to handle your inputs:

import heapq
def m(i): 
    return list(heapq.merge(*i))

print m(((1, 4, 7), (2, 5, 8), (3, 6, 9)))

For the actual function, 59 characters, or the 52 in reduced version:

import heapq
def m(i): return list(heapq.merge(*i))

This also has the benefit of using a tested and true implementation built into Python

Edit: Removed the semi-colons (thanks @Douglas).