Design File System

Intuition

• Check if the path prior to what you are placing is in your hashmap. If it is not, then you would be invalid.
• So this question relies mostly on the hashmap and making sure what leads up to the tail of your path is previously in your hashmap.

Runtime

• CreatePath: $O(W)$ where W is the length of the string.
• get: $O(1)$ through a hashmap search

Code

Hashmap Solution

class FileSystem:
    def __init__(self):
        self.hm = {}
        
    def createPath(self, path: str, value: int) -> bool:
        if path in self.hm:
            return False
            
        split = path.split("/")
        root = "/".join(split[:-1])
 
        if root != "" and root not in self.hm:
            return False
 
        tail = split[-1]
        self.hm[f"{root}/{tail}"] = value
        return True
 
 
    def get(self, path: str) -> int:
        if path in self.hm:
            return self.hm[path]
        return -1

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References

https://leetcode.com/problems/design-file-system/description/