Hello Friends,

I got this assignment and need help to start, I dont need the code at the moment coz I will have to o it my self, but at now I just need hints to start it. The assignment is:

Del command

Time Limit: 1 Second Memory Limit:32768K Special Judge
Total Submit: 64 Accepted Submit: 22
It is required to find out whether it is possible to delete given files from MS-DOS directory executing the DEL command of MS-DOS operation system only once. There are no nested subdirectories.

A note

DEL command has the following format: DEL wildcard

The actual wildcard as well as a full file name can be made up either of a name containing 1 up to 8 characters or of a name and extension, containing up to 3 characters. The point character “.“ separates the extension from the file name. The extension can be empty and this is equivalent to a name without any extension (in this case a wildcard ends with a point). In a wildcard the characters “?” and “*” can be used. A question mark substitutes exactly one character of the full file name excluding a point, an asterisk any sequence of characters (containing no points) even empty one. An asterisk can appear only at the last position of the name and the extension.
MS.DOS system can permit maybe other wildcards but they can not be used in this task. File names and extensions consist only of Latin capitals and digits.

Input

Input contains a list of full file names without empty lines and spaces. Each name is written in a separate line of input data file and preceded with a control sign: “.” For delete or “+” for keep. Full file names are not repeated. The list comprises at least one file, and at least one file is marked to be deleted. There are no more than 1000 files.

Output

Write to the output the required DEL command (only one proposal) or IMPOSSIBLE if there is no solution. A space should separate “DEL” from wildcard.
This problem contains multiple test cases!
The first line of a multiple input is an integer N, then a blank line followed by N input blocks. Each input block is in the format indicated in the problem description. There is a blank line between input blocks.
The output format consists of N output blocks. There is a blank line between output blocks.

Sample Input

1
-BP.EXE
-BPC.EXE
+TURBO.EXE

Sample Output
DEL ?P*.*

Problem Source: Northeastern Europe 1996
Zhejiang University Online Judge VI.0

Regards.

Parsing the file, and producing two lists of files, a 'keep' list and a 'delete' list.

Sorting them might be advantageous as well.

Ok, thanks Salem for your reply, I will try it but if I got any problem, will bother you again.

Regards.

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