Design File System

Medium · Trie · about 20 minutes

Asked at Airbnb, DoorDash, Coinbase, Uber, Snowflake, Capital One, Booking.com, Expedia Group, SoFi, Grab, Swiggy.

Build a store that maps slash-separated paths to integer values.

  • FileSystem() starts with only the root "".
  • createPath(path, value) adds path (for example "/docs/notes") with value and returns true. It

returns false, changing nothing, if path is already present or the path one level up is missing.

  • get(path) returns the value stored at path, or -1 when there is none.

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