Question

I am struggling about a recursion problem, which should not be too hard, but for some reason I don’t come up with a solution.

I have an array of size “n” and I want to count up each element from 0 to n in a way that I get each possible combination.

n = 3
[0,0,0]
[0,0,1]
[0,1,0]
[1,0,0]
[...  ]
[3,3,3]

Can anyone help?

Answer 1

No need for (explicit) recursion:

import itertools
for comb in itertools.product(range(4), repeat=3):
    print comb

produces:

(0, 0, 0)
(0, 0, 1)
(0, 0, 2)
(0, 0, 3)
(0, 1, 0)
(0, 1, 1)
...
(3, 3, 2)
(3, 3, 3)