Longest Absolute File Path

LeetCode_LongestAbsoluteFilePath.py

class Solution:
    def lengthLongestPath(self, input):
        """
        :type input: str
        :rtype: int
        """

        def is_dir(val):
            return False if '.' in val else True

        memo = {}
        to_return = 0
        
        arr = input.split('\n')
        for val in arr:
            n_level = val.count('\t')
            # IS A DIRECTORY
            if is_dir(val):
                if n_level == 0:
                    memo[n_level] = len(val)
                else:
                    memo[n_level] = len(val.replace('\t', '')) + memo[n_level-1]
            # IS A FILE
            else:
                if n_level-1 in memo:
                    length = len(val.replace('\t', '')) + memo[n_level-1] 
                else:
                    length = len(val.replace('\t', ''))
                length += n_level  # to account for the "/" that seperates dir from another dir or file.
                if length > to_return:
                    to_return = length
                    
        return to_return