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
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"
Note
按 “/+” split，遇到“..”pop，遇到不是“.”或者“”就入栈
Code
class Solution {
public String simplifyPath(String path) {
Stack<String> stack = new Stack<>();
String[] paths = path.split("/+");
for (String s : paths) {
if (s.equals("..")) {
if (!stack.isEmpty()) {
stack.pop();
}
} else if(!s.equals(".") && !s.equals(""))
stack.push(s);
}
String res = "";
while (!stack.isEmpty()) {
res = "/" + stack.pop() + res;
}
if (res.length() == 0) {
return "/";
}
return res;
}
}
