Given an absolute path for a file (Unix-style), simplify it. Or in other words, convert it to the canonical path.
In a UNIX-style file system, a period . refers to the current directory. Furthermore, a double period .. moves the directory up a level. For more information, see: Absolute path vs relative path in Linux/Unix
Note that the returned canonical path must always begin with a slash /, and there must be only a single slash / between two directory names. The last directory name (if it exists) must not end with a trailing /. Also, the canonical path must be the shortest string representing the absolute path.
Example 1:
Input: "/home/"
Output: "/home"
Explanation: Note that there is no trailing slash after the last directory name.
Example 2:
Input: "/../"
Output: "/"
Explanation: Going one level up from the root directory is a no-op, as the root level is the highest level you can go.
Example 3:
Input: "/home//foo/"
Output: "/home/foo"
Explanation: In the canonical path, multiple consecutive slashes are replaced by a single one.
Example 4:
Input: "/a/./b/../../c/"
Output: "/c"
Example 5:
Input: "/a/../../b/../c//.//"
Output: "/c"
Example 6:
Input: "/a//b////c/d//././/.."
Output: "/a/b/c"</pre>
AC代码
class Solution {
public:
string simplifyPath(string path) {
vector<string> st;
for (auto& c : path) if (c == '/') c = ' ';
istringstream iss(path);
string word, ans;
while (iss >> word) {
if (word == ".") continue;
else if (word == "..") {
if (st.empty()) continue;
st.pop_back();
}
else st.push_back(word);
}
if (st.empty()) return "/";
for (auto& ele : st) ans = ans + "/" + ele;
return ans;
}
};
他人代码
class Solution {
public:
string simplifyPath(string path) {
string res, t;
stringstream ss(path);
vector<string> v;
while (getline(ss, t, '/')) {
if (t == "" || t == ".") continue;
if (t == ".." && !v.empty()) v.pop_back();
else if (t != "..") v.push_back(t);
}
for (string s : v) res += "/" + s;
return res.empty() ? "/" : res;
}
};
总结
其实可以不先把所有的‘/’换成空格的，getline函数可以接收第三个参数。
另解抄自：https://www.cnblogs.com/grandyang/p/4347125.html
