Task
In the alphabet of the language of the tribe «Tumba-Yumba» four letters: "K", "L", "M" and "N". It is necessary to display on the screen all words consisting of n letters that can be built from the letters of this alphabet
The problem is a normal brute-force problem that can be reduced to a smaller problem.
We will sequentially substitute letters for the word.
The first position of a word can be one of the 4 letters of the alphabet (
K, L, M, N).
First, put the letter '
K' first. Then, in order to get all variants with the first letter '
K', you need to enumerate all possible combinations of letters in the remaining
n-1 positions and .etc. (see picture)
Thus, we came up with a recursive solution: in a loop, go through all possible first letters (putting each letter of the alphabet in turn in the first place) and for each case build all possible "tails"; length
n-1.
Recursive iteration of characters
You need to stop the recursion and output the finished word when the remaining part is empty (
n = 0), i.e. all letters are already selected.
The recursive procedure would look like this:
def TumbaWords(word, alphabet, n):
if n < 1:
print(word)
return
for c in alphabet:
TumbaWords(word+c, alphabet, n - 1)