Mapped Strings Problem

#1

How the recursion tree will be made for this question?

#2

@ashwani225 take the first number, map it to its Alphabet and make recursive call for the remaining .
If the first is number of passed array/string is 1 then consider second number also and make second recursive call for the elements after 2nd number.
If the firs is number 2, then if second number is 0<=k<7 consider second also and call for remaining.

solve(string s, int i, string ans)
{
...
           solve(s,i+1,ans);
...
        if(s[i]=='1')
.
.
.
       solve(s,i+2,ans)

if(s[i]=='2'  && s[i+1]-'0'<=6)
    solve(s,i+2,ans);
.
.
.
}

I have just written the recursive calls to help you figure out the recursion.
I have taken input numbers as string.
If this resolves your doubt mark it as resolved.
#3

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