LeetCode Simplify Path

 1 public class Solution {
 2     public String simplifyPath(String path) {
 3         if(path == null || path.length() == 0){
 4             return path;
 5         }
 6         //split string into array
 7         //when encoutering "." or " ", continue
 8         //when encoutering "..", if stack is not empty, pop stack and return to upper level
 9         //when encoutering else, push into stack.
10         int len = path.length();
11         String [] strArr = path.split("/");
12         Stack<String> stk = new Stack<String>();
13         for(int i = 0; i<strArr.length; i++){
14             if(strArr[i].equals(".")||strArr[i].length() == 0){
15                 continue;
16             }else if(strArr[i].equals("..")){
17                 if(!stk.isEmpty()){
18                     stk.pop();
19                 }
20             }else{
21                 stk.push(strArr[i]);
22             }
23         }
24         
25         StringBuilder sb = new StringBuilder();
26         
27         // Corner case like "///", it should return "/".
28         if(stk.size() == 0){
29             return "/";
30         }
31         
32         //Reverse the stack
33         Collections.reverse(stk);
34         while(!stk.isEmpty()){
35             sb.append("/" + stk.pop());
36         }
37         return sb.toString();
38     }
39 }