[leetcode] 题型整理之字符串处理

71. 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".

java的split函数，只要separator的前“或者”后没有“别的”字符串就会返回一个空。

linux系统当中，多余两个的点会被当作普通路径处理。

public class Solution {
    public String simplifyPath(String path) {
        if (path.length() == 0) {
            return "";
        }
        String[] strs = path.split("/");
        StringBuilder result = new StringBuilder();
        LinkedList<String> stack = new LinkedList<String>();
        for (String string : strs) {
            switch (string) {
                case "": stack.offer("/"); break;
                case ".": break;
                case "..": while (!stack.isEmpty() && stack.removeLast().equals("/")); break;
                default: stack.offer(string);
            }
        }
        if (path.charAt(0) == '/') {
            result.append('/');
        }
        while (!stack.isEmpty()) {
            String string = stack.removeFirst();
            if (!string.equals("/")) {
                result.append(string);
                result.append('/');
            }
        }
        int ll = result.length();
        if (ll > 1 && result.charAt(ll - 1) == '/') {
            result.deleteCharAt(ll - 1);
        }
        return result.toString();
    }
}