Leetcode71. Simplified Paths

题目传送地址： https://leetcode.cn/problems/simplify-path/

运行效率

代码如下

 public static String simplifyPath(String path) {
    
        //因为一个.表示当前目录本身,所以可以直接忽略
        while (path.contains("/./")) {
    
            path = path.replace("/./", "/");
        }
        // '//'都被视为单个斜杠 '/' 任意多个连续的斜杠（即,'//'）都被视为单个斜杠 '/'
        while (path.contains("//")) {
    
            path = path.replace("//", "/");
        }
        if (path.endsWith("/.") && path.length() > 2) {
     // 因为要考虑到 path= /.
            path = path.substring(0, path.length() - 2);
        }
        //此外,两个点 （..） 表示将目录切换到上一级（指向父目录）
        while (path.contains("/../")) {
    
            // //Can't say blindly..就进行处理. 因为...里也包含.. 而...Can be the name of a folder 任何其他格式的点（例如,'...'）均被视为文件/目录名称.
            StringBuilder stringBuilder = new StringBuilder(path);
            int indexOf = path.indexOf("/../");
            int lastIndexOf = path.lastIndexOf("/", indexOf - 1);
            if (lastIndexOf != -1) {
    
                stringBuilder.delete(lastIndexOf, indexOf + 3);
            } else {
    
                stringBuilder.delete(indexOf, indexOf + 3);
            }
            path = stringBuilder.toString();
        }
        if ("/".equals(path)) {
    
            return "/";
        }
        if (path.endsWith("/")) {
    
            path = path.substring(0, path.length() - 1);
        }
        if (path.endsWith("/..") && path.length() > 3) {
     // 因为要考虑到 path= /..
            int i = path.lastIndexOf("/", path.length() - 4);
            path = path.substring(0, i);
            if ("".equals(path)) {
    
                return "/";
            }
        }
        if (path.endsWith("...")) {
    
            return path;
        }
        if ("/..".equals(path)) {
    
            return "/";
        }
        if (path.endsWith(".")) {
    
            path = path.substring(0, path.length() - 1);
        }
        return path;
    }