FileFilter | Topcoder Archive

Problem Statement

You are working on the backend of a system that allows people to upload files. For security reasons, you want to restrict the file extensions of the files they upload. You will be given a String[], extensions, containing a list of allowed extensions. You will also be given a String[], files, containing the names of a number of files. Your task is to return a String[], each element of which is either "ALLOW" or "DENY", corresponding to the elements of files with the same indices. If a filename ends with a period ('.') followed by an allowed extension, ignoring case, then it is to be allowed, otherwise it should be denied.

Definition

Class:: FileFilter
Method:: filter
Parameters:: String[], String[]
Returns:: String[]
Method signature:: String[] filter(String[] files, String[] extensions)
(be sure your method is public)

Constraints

files will contain between 0 and 50 elements, inclusive.
extensions will contain between 0 and 50 elements, inclusive.
Each element of files will contain between 2 and 50 letters ('a'-'z' and 'A'-'Z') and periods.
The last character of each element of files will be a letter.
Each element of files will contain at least one period.
Each element of extensions will contain between 1 and 50 lowercase letters ('a'-'z').

Examples

{"algorithm.txt","algorithms.html","wingl.exe","yourDoc.PIF","graph.gIf"}

{"txt","html","gif","doc"}

Returns: { "ALLOW",  "ALLOW",  "DENY",  "DENY",  "ALLOW" }

```
{}
```
```
{"exe","pif"}
```
```
Returns: { }
```

{".bashrc","bash.rc"}

{"rc"}

Returns: { "DENY",  "ALLOW" }

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