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();
    }
}