71. Simplify Path

Given an?absolute path?for a file (Unix-style),simplify it. Or in other words,convert it to the?canonical path.

In a UNIX-style file system,a period?.?refers to the current directory. Furthermore,a double period?..?moves the directory up a level. For more information,see:?Absolute path?vs?relative?path?in?Linux/Unix

Note that the returned canonical path must always begin?with a slash?/,and there must be only a single slash?/?between two directory names.?The last directory name (if it exists)?must not?end with a trailing?/. Also,the canonical path must be the?shortest?string?representing the absolute path.

?

Example 1:

Input: "/home/"
Output: "/home" Explanation: Note that there is no trailing slash after the last directory name. 

Example 2:

Input: "/../"
Output: "/" Explanation: Going one level up from the root directory is a no-op,as the root level is the highest level you can go. 

Example 3:

Input: "/home//foo/"
Output: "/home/foo" Explanation: In the canonical path,multiple consecutive slashes are replaced by a single one. 

Example 4:

Input: "/a/./b/../../c/"
Output: "/c" 

Example 5:

Input: "/a/../../b/../c//.//"
Output: "/c" 

Example 6:

Input: "/a//b////c/d//././/.."
Output: "/a/b/c"

class Solution {
    public String simplifyPath(String path) {
        String[] strs = path.split("/");
        ArrayList<String> list1 = new ArrayList<String>();
        for(int i = 0; i < strs.length; i++){
        //将空字符串（由类似这种"/a//c"的字符串产生）和 "." （"."代表当前目录不影响路径）去掉，保存到 list1
        if (strs[i].isEmpty() || strs[i].equals(".")) {
            continue;
        }
        list1.add(strs[i]);
        }
        ArrayList<String> list2 = new ArrayList<String>();
        for(int i = 0; i < list1.size(); i++){
            if(list1.get(i).equals("..")){
                if(!list2.isEmpty()){
                    list2.remove(list2.size() - 1);
                }
            } else list2.add(list1.get(i));
        }
        String res = String.join("/",list2);
        res = "/" + res;
        return res;
    }
}

?

这种题真是索然无味

https://leetcode.wang/leetCode-71-Simplify-Path.html