Given an absolute path for a file (Unix-style), simplify it.
For example,
path = "/home/", => "/home"
path = "/a/./b/../../c/", => "/c"
Corner Cases:
- Did you consider the case where path =
"/../"?
In this case, you should return"/". - Another corner case is the path might contain multiple slashes
'/'together,
such as"/home//foo/".
In this case, you should ignore redundant slashes and return"/home/foo".
思路：当碰到..回到上层路径，.还是当前路径，由此可知用栈即可实现。
class Solution {
public:
string simplifyPath(string path) {
string simple = "";
stack<string> S;
stack<string> S2;
if(path.empty()) {
return simple;
}
int i, len = path.length(),j;
string str = "";
for(i=1; i<len; ++i) {
if (path[i] == '/' || i==len-1) {
if (i==len-1 && path[i]!='/') {
str += path[i];
}
if (!str.empty()) {
if (str == "..") {
str.clear();
if (!S.empty()) {
S.pop();
}
continue;
}
if (str == ".") {
str.clear();
continue;
}
S.push(str);
str.clear();
}
}
else {
str += path[i];
}
}
if (S.empty()) {
return "/";
}
while(!S.empty()) {
S2.push(S.top());
S.pop();
}
while(!S2.empty()) {
simple += '/';
simple += S2.top();
S2.pop();
}
return simple;
}
};