Given a string representing the file system, return the length of the longest absolute path to a file in the abstracted file system.

Daily_coding_Problem_17.py

'''
Suppose we represent our file system by a string in the following manner:
The string "dir\n\tsubdir1\n\tsubdir2\n\t\tfile.ext" represents:

dir
    subdir1
    subdir2
        file.ext
The directory dir contains an empty sub-directory subdir1 and a sub-directory subdir2 containing a file file.ext.

The string "dir\n\tsubdir1\n\t\tfile1.ext\n\t\tsubsubdir1\n\tsubdir2\n\t\tsubsubdir2\n\t\t\tfile2.ext" represents:

dir
    subdir1
        file1.ext
        subsubdir1
    subdir2
        subsubdir2
            file2.ext
The directory dir contains two sub-directories subdir1 and subdir2. 
subdir1 contains a file file1.ext and an empty second-level sub-directory subsubdir1. 
subdir2 contains a second-level sub-directory subsubdir2 containing a file file2.ext.

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.
Note:
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.
'''
class Node:
    def __init__(self,name):
        self.name=name
        self.is_file=False
        self.next=[]
        
class File_System:
    def __init__(self):
        self.root=None
        self.stack=[]
        self.has_file=False
        
    def add_dir(self,path):
        curr_par=self.stack[-1]
        if curr_par.name.count('\t') >= path.count('\t'):
            while(curr_par.name.count('\t') != path.count('\t')):
                self.stack.pop()
                curr_par=self.stack[-1]
            self.stack.pop()
            curr_par=self.stack[-1]
        dir_node=Node(path)
        if '.ext' in path:
            dir_node.is_file=True
            self.has_file=True
        curr_par.next.append(dir_node)
        if dir_node.is_file is False:
            self.stack.append(dir_node)
     
    def create(self,fs_string):
        if len(fs_string) is 0:
            return
        paths=fs_string.split('\n')
        for path in paths:
            if self.root==None:
                self.root=Node(path)
                self.is_file=False
                self.stack.append(self.root)
            else:
                self.add_dir(path)
                
    def get_path(self):
        if self.has_file is False:
            return 0
        queue=[]
        queue.append((self.root,self.root.name))
        long_path=len(self.root.name)
        while(len(queue)!=0):
            node_path=queue.pop(0)
            for i in range(len(node_path[0].next)):
                if node_path[0].next[i].is_file == True:
                    long_path=max(long_path,len(node_path[1]+'/'+node_path[0].next[i].name.replace('\t','')))
                else:
                    queue.append((node_path[0].next[i], \
                                  (node_path[1]+"/"+node_path[0].next[i].name).replace('\t','')))
        return long_path
    
if __name__=="__main__":
    fs_path="dir\n\tsubdir1\n\t\tfile1.ext\n\t\tsubsubdir1\n\tsubdir2\n\t\tsubsubdir2\n\t\t\tfile2.ext"
    fs=File_System()
    fs.create(fs_path)
    print(fs.get_path())