Simplify Path

public class Solution {
    public String simplifyPath(String path) {
        if(path==null||path.length()==0) return path;
        String[] s = path.split("/");
        LinkedList<String> st = new LinkedList<String>();
        String res = new String();
        for(String tmp:s){
            //if(tmp.equals(".")||tmp.equals("/")){ 因为split已经去除多余的/了
            if(tmp.length()==0||tmp.equals(".")){
                continue;
            //}else if(tmp.equals("..")&&!st.isEmpty()){ //Input:    "/.."
             //   st.pop();
            }else if(tmp.equals("..")){
                if(!st.isEmpty())
                    st.pop();
            }else
                st.push(tmp);
        }
        if(st.isEmpty())
            return "/";
        while(!st.isEmpty()){
            res +="/" + st.removeLast();
        }
        return res;
        
    }
}