Tidy up a file path
A storage service is handed paths with stray slashes and dot segments in them, and stores exactly one canonical form.
- Segments are separated by slashes; runs of slashes count as one.
- A "." segment means "here" and is dropped.
- A ".." segment climbs one level; at the root it does nothing.
- The result starts with a slash and, apart from the root, does not end with one.
- The root itself is a single slash.
tidyPath(raw: string) → string
C++ needs a compiler and Drill does not host one yet, so this page is the reference rather than an exercise: the problem, worked examples, and the solution in full. To type it out, the same problem runs in Python.
Where you start
std::string tidyPath(std::string raw) {
}Worked examples
| Call | Result |
|---|---|
tidyPath(std::string("/home//user/")) | std::string("/home/user") |
tidyPath(std::string("/a/./b/../c")) | std::string("/a/c") |
tidyPath(std::string("/../")) | std::string("/") |
tidyPath(std::string("/")) | std::string("/") |
Hint
Split on the slash and push each real segment onto a stack; ".." pops instead. Joining the stack back up gives the answer.
Reference solution in C++
std::string tidyPath(std::string raw) {
std::vector<std::string> kept;
std::stringstream stream(raw);
std::string part;
while (std::getline(stream, part, '/')) {
if (part.empty() || part == ".") continue;
if (part == "..") {
if (!kept.empty()) kept.pop_back();
} else {
kept.push_back(part);
}
}
std::string result = "/";
for (size_t i = 0; i < kept.size(); i++) {
if (i > 0) result += "/";
result += kept[i];
}
return result;
}