华为OD机试-2024年E卷-模拟目录管理 JAVA
图中题和这个类似：
* 题目描述 * 实现一个模拟目录管理功能的软件，输入一个命令序列，输出最后一条命令运行结果。支持命令：创建目录命令：mkdir 目录名称，如 mkdir abc 为在当前目录创建abc目录， * 如果已存在同名目录则不执行任何操作。此命令无输出。进入目录命令：cd 目录名称，如 cd abc 为进入abc目录，特别地，cd .. 为返回上级目录，如果目录不存在则不执行任何操作。 * 此命令无输出。查看当前所在路径命令：pwd，输出当前路径字符串。约束：目录名称仅支持小写字母；mkdir 和 cd 命令的参数仅支持单个目录， * 如：mkdir abc 和 cd abc；不支持嵌套路径和绝对路径，如 mkdir abc/efg，cd abc/efg，mkdir /abc/efg，cd /abc/efg 是不支持的。 * 目录符号为/，根目录/作为初始目录。任何不符合上述定义的无效命令不做任何处理并且无输出。 * 输入描述* 输入 N 行字符串，每一行字符串是一条命令。* 输出描述* 输出最后一条命令运行结果字符串。 * 备注* 命令行数限制100行以内，目录名称限制10个字符以内。 * 用例1 * 输入 * mkdir abc * cd abc * pwd * 输出 * /abc/ * 说明：在根目录创建一个abc的目录并进入abc目录中查看当前目录路径，输出当前路径/abc/
不支持嵌套目录的写法如下：
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
//同OJTest2
class DirNode {
private String dirName; //定义当前节点的目录名称
private DirNode parent;//定义父类的Node节点
private List<DirNode> children; //定义子类的节点列表，可能有多个同级子目录
public DirNode(String dirName) {
this.dirName = dirName;
parent = null;
children = new ArrayList<>();
}
public void addChildren(DirNode node) {
children.add(node);
node.parent = this;
}
public String getDirName() {
return dirName;
}
public DirNode getParent() {
return parent;
}
public List<DirNode> getChildren() {
return children;
}
}
class DirectoryDir {
DirNode root;
public DirectoryDir() {
this.root = new DirNode("/");
}
public void mkdir(String path) {
if (path.startsWith("/")) {
path = path.substring(1);
}
if (!path.contains("/")) { //如果path中没有嵌套目录的话，才能在当前root节点下创建目录
boolean flag = false;
for (DirNode child : root.getChildren()) {
if (child.getDirName().equals(path)) {
flag = true;
break;
}
}
if (!flag) {
DirNode node = new DirNode(path);
root.addChildren(node);
}
}
}
public void cd(String path) {
if (path.equals("..")) {
if (root.getParent() != null) {
root = root.getParent();
}
} else {
if (path.startsWith("/")) {
path = path.substring(1);
}
if (!path.contains("/")) {
DirNode current = root;
for (DirNode child : current.getChildren()) {
if (child.getDirName().equals(path)) {
current = child;
break;
}
}
root = current;
}
}
}
public String pwd() {
StringBuilder bd = new StringBuilder();
DirNode current = root;
List<String> lists = new ArrayList<>();
if (!current.getDirName().equals("/")) { //如果当前不在根目录
do {
lists.add(current.getDirName());
current = current.getParent();
} while (current != null);
} else {
return bd.append("/").toString();
}
for (int i = lists.size() - 1; i >= 0; i--) {
bd.append(lists.get(i)).append("/");
}
return bd.substring(1);
}
}
public class DirManage {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
DirectoryDir directoryTree = new DirectoryDir();
while (in.hasNextLine()) {
String command = in.nextLine();
if (command.startsWith("mkdir")) {
String dirName = command.split(" ")[1];
directoryTree.mkdir(dirName);
} else if (command.startsWith("cd")) {
String dirName = command.split(" ")[1];
directoryTree.cd(dirName);
} else if (command.equals("pwd")) {
System.out.println(directoryTree.pwd());
}
}
}
}
支持嵌套创建目录和嵌套cd目录的方式如下：
class DirectoryNode {
private String dirName; //定义目录名称
private DirectoryNode parent; //定义父节点
private List<DirectoryNode> children; //定义孩子节点
public DirectoryNode(String dirName) {
this.dirName = dirName;
this.parent = null;
this.children = new ArrayList<>();
}
//添加子目录节点
public void addChild(DirectoryNode node) {
children.add(node);
node.parent = this;
}
//获取当前目录名称
public String getDirName() {
return dirName;
}
//获取父目录节点
public DirectoryNode getParent() {
return parent;
}
//获取子目录节点
public List<DirectoryNode> getChildren() {
return children;
}
}
class DirectoryTree {
private DirectoryNode root;
public DirectoryTree() {
this.root = new DirectoryNode("/");
}
//创建目录
public void mkdir(String path) {
if (path.startsWith("/")) {
path = path.substring(1);
}
String[] dirNames = path.split("/");
DirectoryNode current = root;
for (String dirName : dirNames) {
boolean found = false;
for (DirectoryNode child : current.getChildren()) {
if (child.getDirName().equals(dirName)) {
current = child;
found = true;
break;
}
}
if (!found) {
DirectoryNode newDir = new DirectoryNode(dirName);
current.addChild(newDir);
current = newDir;
}
}
}
public void cd(String path) {
if (path.equals("..")) { //向后退一层目录到当前的parents层
if (root.getParent() != null) {
root = root.getParent();
}
} else { //进入到目录里
if (path.startsWith("/")) {
path = path.substring(1);
}
String[] dirNames = path.split("/");
DirectoryNode current = root;
for (String dirName : dirNames) {
for (DirectoryNode child : current.getChildren()) {
if (child.getDirName().equals(dirName)) {
current = child;
break;
}
}
}
root = current;
}
}
public String pwd() {
StringBuilder currentPath = new StringBuilder();
DirectoryNode current = root;
List<DirectoryNode> pathNodes = new ArrayList<>();
while (current != null) {
pathNodes.add(current);
current = current.getParent();
}
for (int i = pathNodes.size() - 1; i >= 0; i--) {
currentPath.append(pathNodes.get(i).getDirName()).append("/");
}
return currentPath.substring(1);
}
}
public class OJTest2 {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
DirectoryTree directoryTree = new DirectoryTree();
while (in.hasNextLine()) {
String command = in.nextLine();
if (command.startsWith("mkdir")) {
String dirName = command.split(" ")[1];
directoryTree.mkdir(dirName);
} else if (command.startsWith("cd")) {
String dirName = command.split(" ")[1];
directoryTree.cd(dirName);
} else if (command.equals("pwd")) {
System.out.println(directoryTree.pwd());
}
}
in.close();
}
}
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