71. Simplify Path

Deque Stack, String[] strings = path.split("/");

class Solution {
    public String simplifyPath(String path) {
        // use Deque as Stack, LinkedList implementation
        // method: deque.size()
        Deque<String> memo = new LinkedList<>();
        
        // get all substrings in between "/"
        // method: string.split(string), may get empty string
        String[] strings = path.split("/");
        for(String str : strings){
            // compare sting: string.equals(string);
            if(str.equals("..") && memo.size()>0){
                // deque.pop() retrive and remove the first element of deque
                memo.pop();
            }else if(!str.equals("..") && !str.equals(".") && !str.equals("")){
                memo.push(str);
            }
        }
        
        StringBuilder result = new StringBuilder();
        while(memo.size()>0){
            result.append('/'+memo.removeLast());
        }
        return result.length()>0? result.toString() : "/";
    }
}