Did not understand where to start

#1

Give me a clue because i can’t able to understand its recursive solution and brute force solution too.

#2

in mapped strings problem, it is given that there is a map which stores numbers from 1 to 26 which are correspondingly mapped from A to Z.
1 -> A
2 -> B
3 -> C
.
.
25 -> Y
26 -> Z

Now you have to print all the possible strings which we can form from given input number.
For eg.
input : 123
Now, the different ways in which we can divide string 123 are:
1-2-3 => A-B-C
1-23 => A-W
12-3 => L-C
the hint is that in the recursive call n/10 or something similar to this will be passed.