• 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".

 class Solution {

 public:

     void handleEntry(vector<string> &path_stack, string path_entry) {

         if(path_entry == "..") {

             if(path_stack.size() > )

                 path_stack.pop_back();

         }else if (path_entry != ".")

                 path_stack.push_back(path_entry);

     }

     string simplifyPath(string path) {

         string simple_path;

         if(path.size() == )

             return simple_path;

         vector<string> path_stack;

         string path_entry;

         for(int i = ; i < path.size(); i ++) {

             if(path_entry.size() ==  && path[i] == '/'){

                 continue;

             }else if (path_entry.size() !=  && path[i] == '/') {

                 handleEntry(path_stack, path_entry);

                 path_entry.clear();

             }else {

                 path_entry.push_back(path[i]);

             }

         }

         if(path_entry.size() > )

             handleEntry(path_stack, path_entry);

         for(string item: path_stack) {

             simple_path += "/";

             simple_path += item;

         }

         if(simple_path.size() == )

             return "/";

         return simple_path;

     }

 };