Find Directory Destination

Related: LeetCode 71 - Simplify Path
String cd(String origin, String path) ;Input: Origin (current directory), Path(a relative path)Output: Return destination path，Follow-up: what if path is an absolute path? just ignore origin to process path类似LC71

//O(n)
public static String commandCd(String origin,String path){
         if(path==null||origin==null)return origin;
         Stack<String> dir = new Stack<String>();
         String o[] = origin.split("/");
         for(String ss : o){
             if(ss!=null&&ss.length()>0) dir.push(ss);
                //You must control what store in stack

         }
         String p[] = path.split("/");
         for(String c : p){
             if(c.equals(".")||c.equals(""))continue;
             else if(c.equals("..")&&!dir.isEmpty()) dir.pop();
             else if(!c.equals("..")) dir.push(c);
         }
         //print out
         StringBuilder sb = new StringBuilder(origin.length()+path.length());
         if(dir.isEmpty())sb.append("/");
         while(!dir.isEmpty()){
             sb.insert(0,dir.pop());
             sb.insert(0,"/");
         }
         return sb.toString();
     }