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Filesystem

Time limit1sMemory limit1024 MB

Summary
Simulate a small file system with echo, cp, mv, rm, mkdir, and rmdir commands, then print each queried file's contents or invalid!.
Level

Medium4 of 10

Topics
Simulation, String, Tree
Solved
No attempts yet

Problem

Given a series of file system commands and queries, output the contents of the file requested by each query. Each query is a filename to print. If a query is invalid (for example, its path does not exist), print invalid!.

Support the following commands:

  • echo "<content>" > <path>: Writes <content> to the file at <path>. If <path> exists, it must be a file, and its contents are replaced. If it does not exist, its parent directory must exist, and the file is created. <content> contains only ASCII digits, letters, *, ?, <, >, and spaces.
  • cp <source> <destination>: Copies the file <source> to <destination>. If <destination> already exists and is a directory, the file is copied into that directory under the final path component of <source>. Otherwise, <destination> is the new filename, and its parent directory must already exist. The new file replaces any existing content.
  • mv <source> <destination>: Moves the file or directory <source> to <destination>. As with cp, if <destination> already exists and is a directory, the source is moved into it under the final path component of <source>. Otherwise, <destination> is the new name, and its parent directory must already exist. The new file replaces any existing content, and <source> is removed.
  • rm <path>: Deletes the file at <path>.
  • mkdir <path>: Creates a directory at <path>. The parent directory must already exist.
  • rmdir <path>: Removes an empty directory at <path>.

All paths contain only digits, letters, or /. A path is at most 31 characters and has at most 7 components, separated by /. All commands in the input are valid. Unless specified above, no command refers to a path that does not exist or is invalid. Each command is shorter than 1024 characters.

Input

The first line contains T (0 < T < 100), the number of test cases.

Each test case starts with a line containing C (0 < C < 100), the number of commands. The next C lines contain the commands that build the filesystem. The starting folder may be ignored, so the current directory (./) can be assumed.

The next line contains Q (0 < Q < 20), the number of filenames to print. The next Q lines contain the filenames, which may include a path such as myfolder/myfile.

Output

For each query, print the contents of the requested file, or invalid! if the file does not exist. Print a blank line after each test case.

Examples1

  1. Example 1

    Input
    2
2
echo "This is foo" > foo
cp foo bar
2
foo
bar
3
mkdir dir
echo "Bar" > bar
mv bar dir/bar
1
bar
    Expected output
    This is foo
This is foo

invalid!