71. Simplify Path

Leetcode String Stack

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".

/**
 * Given an absolute path for a file (Unix-style), simplify it.
 *
 * https://leetcode.com/problems/simplify-path/description/
 *
 * 使用stack处理，需要注意得是可能会出现"/.."的情况，
 * 所以要判断stack.isEmpty()；
 * 也需要注意空的情况，需要判断stack.size()==0。
 *
 *
 * 
 */
public class Q71SimplifyPath {
    public static String simplifyPath(String path) {
        Stack<String> stack = new Stack<>();
        for (String s: path.split("/")) {
            switch (s) {
                case "":
                    break;
                case ".":
                    break;
                case "..":
                    if (!stack.isEmpty())
                        stack.pop();
                    break;
                default:
                    stack.push(s);
                    break;
            }
        }

        if (stack.size()==0) {
            return "/";
        }


        StringBuilder newPath = new StringBuilder();
        for (String s: stack) {
            newPath.append("/");
            newPath.append(s);
        }
        return newPath.toString();
    }
}