Meta Online Coding Assessment: Simplify Unix File Path

You're asked to implement a function that takes an absolute Unix-style path and returns its canonical simplified path. The input always begins with a leading slash (/), and your result must start with a single slash, separate directory names with one slash, remove "." components, resolve ".." to move up one level, collapse consecutive slashes, and never end with a slash unless the result is root (/).

A practical approach is to parse the string and process components left-to-right. Split on "/" (or scan and extract segments), then use a stack (or list) to:

• ignore empty segments and single-period (".") segments
• pop the stack for double-period ("..") segments when possible
• push any valid directory name (including names like "...")

Finally, join the stack with "/" and prefix a leading slash (or return "/" if the stack is empty).

Skill signals interviewers look for: robust string parsing, correct handling of edge cases (multiple slashes, trailing slashes, sequences of periods that are valid names), use of a stack or deque, and time/space complexity reasoning. Expect the interviewer to ask for complexity (O(n) time, O(n) extra space) and to probe alternative implementations (in-place string modification, one-pass parsing, or handling relative paths and symbolic links). Test your code with many edge cases and sample paths before submitting.