This problem was asked by Google.
Suppose we represent our file system by a string in the following manner:
dir subdir1 subdir2 file.ext
dir contains an empty sub-directory
subdir1 and a sub-directory
subdir2 containing a file
dir subdir1 file1.ext subsubdir1 subdir2 subsubdir2 file2.ext
dir contains two sub-directories
subdir1 contains a file
file1.ext and an empty second-level sub-directory
subdir2 contains a second-level sub-directory
subsubdir2 containing a file
We are interested in finding the longest (number of characters) absolute path to a file within our file system. For example, in the second example above, the longest absolute path is
"dir/subdir2/subsubdir2/file2.ext", and its length is 32 (not including the double quotes).
Given a string representing the file system in the above format, return the length of the longest absolute path to a file in the abstracted file system. If there is no file in the system, return 0.
The name of a file contains at least a period and an extension.
The name of a directory or sub-directory will not contain a period.