Problem Statement (English original)
You are given a current working directory cwd (an absolute Unix-style path) and a cd(arg) string which can be either an absolute path (starts with /) or a relative path (may include segments . and ..).
Implement a function that returns the normalized absolute path after applying cd(arg) from cwd.
Rules:
- Path separator is
/. .means“stay in the same directory”...means“go to parent directory”(but never above root).- Collapse multiple slashes and remove trailing slash (except for root
/). - The output must always be an absolute path.
Examples (from the prompt):
cwd |
cd(arg) |
output |
|---|---|---|
/ |
foo |
/foo |
/baz |
/bar |
/bar |
/foo/bar |
../../../../.. |
/ |
/x/y |
./p/../q |
/x/q |
/x/y |
/p/./q |
/p/q |
Brief Summary / Idea (EN)
Use a stack: start from [] for absolute arg, or from split cwd for relative. Iterate components: skip empty & ., pop on .., push names otherwise. Join with /; if empty, return /. Time/space O(L).
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