Recursion mapped string

#1

i couldn’t think about its approch.
please guide me for approch

#2

@prince43055kumar
You can solve this question recursively. Here given input string consist of only numeric values and you have to find all possible alphabetic string which can be formed using given string. So what you can do is pass the input string to recursive function then you have to options
1)check it first character, save it’s alphabetic form and pass remaining string again to recursive function.
2) check first two character if combination of them is less than 27, save its alphabetic form and pass remaining string again to reccursive function.