388. 文件的最长绝对路径

class Solution:
    def lengthLongestPath(self, input: str) -> int:
        stack, ans = [], 0
        for node in input.splitlines():
            name = node.lstrip('\t')
            level = len(node) - len(name)
            stack = stack[:level]
            stack.append(name)
            if '.' in name:
                ans = max(len('/'.join(stack)), ans)
        return ans