题目:
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"
代码:
string simplifyPath(string path) {
int len = path.length();
if (len == 0)return "/";
string res;
vector<string> pathelement;
int i = 0;
while (i<len) {
while (i<len && path[i] == '/') {
i++;
}
string::size_type index = path.find('/',i);
if (index == string::npos) {
string s = path.substr(i);
if (s == "..") {
if (pathelement.size() > 0) {
pathelement.pop_back();
}
}
else if (s != "."&&s!="") {
pathelement.push_back(s);
}
break;
}
else {
string s = path.substr(i, index-i);
//path = path.substr(index + 1);
if (s == "..") {
if (pathelement.size() > 0) {
pathelement.pop_back();
}
}
else if (s != ".") {
pathelement.push_back(s);
}
i = index + 1;
}
}
for (int i = 0; i < pathelement.size(); i++) {
res += '/' + pathelement[i];
}
if (res.length() == 0)res = "/";
return res;
}
想法:
需要考虑全面点