[LeetCode] 71. Simplify Path

ProblemGiven an absolute path for a file (Unix-style), simplify it. For example,path = “/home/”, => “/home"path = “/a/./b/../../c/”, => “/c"path = “/a/../../b/../c//.//”, => “/c” //here: b is cancelled out, a is cancelled outpath = “/a//b////c/d//././/..”, => “/a/b/c” //here d is cancelled outIn a UNIX-style file system, a period (’.’) refers to the current directory, so it can be ignored in a simplified path. Additionally, a double period (”..”) moves up a directory, so it cancels out whatever the last directory was. For more information, look here: https://en.wikipedia.org/wiki...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”.Solutionclass Solution { public String simplifyPath(String path) { Deque<String> stack = new ArrayDeque<>(); Set<String> ignore = new HashSet<>(Arrays.asList(””, “.”, “..”)); for (String dir: path.split(”/")) { if (!stack.isEmpty() && dir.equals("..")) stack.pop(); if (!ignore.contains(dir)) stack.push(dir); } String res = “”; while (!stack.isEmpty()) { res = “/"+stack.pop()+res; } if (res.equals(”")) return “/”; return res; }}