Simplify Path

Given an absolute path for a file (Unix-style), simplify it.

For example,
path = "/home/", => "/home"
path = "/a/./b/../../c/", => "/c"

click to show corner cases.

Corner Cases:

 

Did you consider the case where path = "/../"?
In this case, you should return "/".

Another corner case is the path might contain multiple slashes '/' together, such as "/home//foo/".
In this case, you should ignore redundant slashes and return "/home/foo".

这一题思路很清晰，使用stack来做。只是最后输出的时候要以队列的方式输出。

/../ 返回上一层

/./ 当前层

 1 public class Solution {
 2     public String simplifyPath(String path) {
 3         // Start typing your Java solution below
 4         // DO NOT write main() function
 5         if(path == null) return null;
 6         String[] element = path.split("/");
 7         Stack<String> st = new Stack<String>();
 8         for(int i = 0; i < element.length; i ++){
 9             if(element[i].length() != 0){
10                 if(element[i].equals("..")){
11                     if(st.isEmpty() != true)
12                         st.pop();
13                 }else if(element[i].equals(".")){
14                 }else{
15                     st.push(element[i]);
16                 }
17             }
18         }
19         StringBuffer sb = new StringBuffer();
20         if(st.isEmpty() == true){
21             sb.append("/");
22         }else{
23             for(int i = 0; i < st.size(); i ++){
24                 sb.append("/");
25                 sb.append(st.elementAt(i));
26             }   
27         }
28         return sb.toString();
29     }
30 }

 第三遍：

 1 public class Solution {
 2     public String simplifyPath(String path) {
 3         String[] parts = path.split("/");
 4         LinkedList<String> ll = new LinkedList<String> ();
 5         for(int i = 0; i < parts.length; i ++){
 6             System.out.println(parts[i]);
 7             if(parts[i].equals("") || parts[i].equals(".") || (parts[i].equals("..") && ll.size() == 0)) continue;
 8             else if(parts[i].equals("..") && ll.size() != 0) ll.removeLast();
 9             else ll.add(parts[i]);
10         }
11         StringBuffer sb = new StringBuffer();
12         while(ll.size() != 0){
13             sb.append("/");
14             sb.append(ll.remove());
15         }
16         if(sb.length() == 0) sb.append("/");
17         return sb.toString();
18     }
19 }

 

posted on 2013-10-02 04:18  Step-BY-Step  阅读(347)  评论(0)  编辑  收藏  举报

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