FunctionDependency

You are developing a database platform that supports, among other things, user defined functions. User-defined functions may call internal functions, other user-defined functions, or both. A user-defined function, FuncA, is said to be dependent on another function, FuncB, if it calls FuncB.

You have been tasked with writing a module that will "script" (list out the code for) all of the functions in a given database. However, because of dependency issues, they must be scripted in a specific order that meets the following criteria:

• A function cannot be scripted until all of its dependent functions have already been scripted.
• Whenever more than one function could be scripted (subject to the first requirement), the one whose name occurs first lexicographically will be scripted first.

You are given a String[] funcs, each element of which is the name of a function in the database. You are also given a String[] depends, a list describing the dependency of each function. Each element of depends is a space-delimited list of integers. Each element of depends corresponds to the element of funcs with the same index. Each number represented in each element of depends refers to the 0-based index of another function.

For instance, suppose a database has two functions, A and B, each of which is dependent on a third function, C. The input might then be given by:

{"B", "C", "A"}
{"1", "", "1"}

Now, since functions A and B both depend upon C, we have to script C first. After that, either A or B could be scripted, since C has already been scripted. We use the second rule to determine that we should script A first. Our return is thus:

{"C", "A", "B"}

You are to return a String[] containing the names of the functions in the order in which they should be scripted.