Simplify Path（路径简化）

问题：

来源：https://leetcode.com/problems/simplify-path

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

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

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".

思路：

先将路径按照“/”切分，然后遍历切分后的路径，利用栈的思想，遇到“”或者“.”就忽略，遇到“..”就出栈（除非栈中没有元素），遇到其他字符串就入栈，最后将栈中的字符串用“/”拼接起来

 import java.util.Stack;
 class Solution {
     public String simplifyPath(String path) {
         String[] subpaths = path.split("/");
         Stack<String> stack = new Stack<String>();
         for(String subpath: subpaths) {
             if(subpath.equals(".") || subpath.equals("")) {
                 continue;
             } else if(subpath.equals("..")) {
                 if(!stack.isEmpty()) {
                     stack.pop();
                 }
             } else {
                 stack.push(subpath);
             }
         }
         StringBuilder stringBuilder = new StringBuilder();
         for(String subpath: stack) {
             stringBuilder.append("/" + subpath);
         }
         if(stringBuilder.length() == 0) {
             stringBuilder.append("/");
         }
         return stringBuilder.toString();
     }
 }