Leetcode 71. Simplify Path

原题：
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"

.

解决方法：
用deque来保存读到的路径，用stringstream来切分字符串。当读到".."时，deque删除最后一个路径。最后把所有读到的路径拼起来即可。

代码：

string simplifyPath(string path) {
deque<string> d;

string res, temp;
stringstream s(path);
while(getline(s,temp, '/')){
if (temp.empty() || temp ==".")
continue;

if (temp == ".."){
if (!d.empty())
d.pop_back();
}else{
d.push_back(temp);
}
}

for(auto item: d){
res +=  "/" + item;
}

return res.empty() ? "/" : res;
}