recursive function

[cesco]

Neil Cerutti wrote:
> On 2007-01-08, cesco <fd.calabrese at gmail.com> wrote:
> > Hi,
> >
> > I have a dictionary of lists of tuples like in the following example:
> > dict = {1: [(3, 4), (5, 8)],
> >         2: [(5, 4), (21, 3), (19, 2)],
> >         3: [(16, 1), (0, 2), (1, 2), (3, 4)]]
> >
> > In this case I have three lists inside the dict but this number
> > is known only at runtime. I have to write a function that
> > considers all the possible combinations of tuples belonging to
> > the different lists and return a list of tuples of tuples for
> > which the sum of the first element of the most inner tuple is
> > equal to N.
> >
> > For example, assuming N = 24, in this case it should return:
> > [((3, 4), (5, 4), (16, 1)), ((3, 4), (21, 3), (0, 2)), ((5, 8), (19,
> > 2), (0, 2))]
>
> What do you mean by "most inner tuple"?
>
> > A simple list comprehension would be enough if only I knew the
> > number of keys/lists beforehand
>
> len(dict.keys()).

What I mean is that the number of keys/lists is not known until runtime
and it changes randomly from time to time which means I would have to
write every time a different list comprehension (or a different number
of nested loops) to accomplish the same thing.
In the example the result of the search should be a list containing
three tuples each of which contains again three tuple (the most inner
tuples). If you consider the first element of each tuple the sum is 24
(like in 3+5+16, or 3+21+0 or 5+19+0).

Any other help will be appreciated