5. Simplify Path

//Deque

class Solution {
    public String simplifyPath(String path) {
        Deque<String> s = new LinkedList<>();
        StringBuilder res = new StringBuilder();
        String[] p = path.split("/");
        
        for(String str : p){
            if(!str.isEmpty() && str.equals("..")) s.poll();
            else if (!str.equals("") && !str.equals(".")) 
                s.push(str);
        }
        
        if(s.isEmpty()) return "/";
        while(!s.isEmpty()){
            //res.insert(0, s.pop()).insert(0, "/");
            // /a/b...
            res.append("/").append(s.pollLast());
        }
        
        return res.toString();
    }
}