simplifyPath.py

# Given an absolute file path (Unix-style), shorten it to the format /<dir1>/<dir2>/<dir3>/....

# Here is some info on Unix file system paths:

# / is the root directory; the path should always start with it even if it isn't there in the given path;
# / is also used as a directory separator; for example, /code/fights denotes a fights subfolder in the code folder in the root directory;
# this also means that // stands for "change the current directory to the current directory"
# . is used to mark the current directory;
# .. is used to mark the parent directory; if the current directory is root already, .. does nothing.
# Example

# For path = "/home/a/./x/../b//c/", the output should be
# simplifyPath(path) = "/home/a/b/c".

# Here is how this path was simplified:
# * /./ means "move to the current directory" and can be replaced with a single /;
# * /x/../ means "move into directory x and then return back to the parent directory", so it can replaced with a single /;
# * // means "move to the current directory" and can be replaced with a single /.

# Input/Output

# [time limit] 4000ms (py)
# [input] string path

# A line containing a path presented in Unix style format. All directories in the path are guaranteed to consist only of English letters.

# Constraints:
# 1 ≤ path.length ≤ 5 · 104.

# [output] string

# The simplified path.


def simplifyPath(path):
    parts = path.split('/')
    simple = []
    for part in parts:
        if part in ['.', '']:
            continue
        elif part == '..':
            if len(simple) > 0:
                simple.pop()
        else:
            simple.append(part)
    path2 = ''
    for i in simple:
        path2 += '/' + i
    if not path2:
        path2 = '/'
    return path2