71. Simplify Path

这道题用栈特别方便

string simplifyPath(string path) {
        stack<string>a_path;
        path+='/';
        for(int i=1;i<path.length();++i){
            if(path[i]=='/')continue;
            else if(path[i]=='.'&&path[i+1]=='.'&&path[i+2]=='/'){
                if(!a_path.empty())a_path.pop();
            }
            else if(path[i]=='.'&&path[i+1]=='/')continue;
            else{
                string temp_path="/";
                while(path[i]!='/'){
                    temp_path+=path[i];
                    ++i;
                }
                a_path.push(temp_path);
            }
        }
        string res_path="";
        while(!a_path.empty()){
            res_path=a_path.top()+res_path;
            a_path.pop();
        }
        if(res_path.empty())res_path+='/';
        return res_path;
    }
    ```