Longest Absolute File Path

Twice the number of downvotes. Be quick to learn.

The problem is to find the length of the longest absolute path to a file in the given file system. We can solve this problem by simulating the file system’s hierarchy using a stack and keeping track of the current path’s length.

Here’s the code for the solution:

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class Solution:
    def lengthLongestPath(self, input: str) -> int:
        stack = [] # To keep track of the length of the path at each depth
        max_length = 0 # To store the length of the longest absolute path to a file
        
        # Split the input by '\n' to iterate through files and directories
        for line in input.split('\n'):
            # Count the number of tabs to find the depth
            depth = line.count('\t')
            # Remove the tabs to get the name
            name = line[depth:]
            
            # If the stack is deeper than the current depth, pop elements from the stack
            while len(stack) > depth:
                stack.pop()
            
            # If the stack is empty, the current length is the length of the name
            # Otherwise, it is the length at the previous depth plus the length of the name plus 1 (for the '/')
            current_length = len(name) if not stack else stack[-1] + len(name) + 1
            stack.append(current_length)
            
            # If the name represents a file (contains '.'), update the max_length
            if '.' in name:
                max_length = max(max_length, current_length)
        
        return max_length

Explanation:

We split the input by ‘\n’ and iterate through files and directories.
We use the stack to keep track of the current length at each depth.
We update the stack based on the depth and whether the name represents a file or directory.
We return the length of the longest absolute path to a file.

This solution processes each file and directory name in the input and efficiently keeps track of the current path’s length using a stack, satisfying the given constraints and requirements.