feat: add solutions to lc problem: No.0588

No.0588.Design In-Memory File System

Author: yanglbme

solution/0500-0599/0588.Design In-Memory File System/README.md

@@ -71,22 +71,266 @@ fileSystem.readContentFromFile("/a/b/c/d"); // 返回 "hello"</pre>
 
 <!-- 这里可写通用的实现逻辑 -->
 
+**方法一：前缀树**
+
+哈希表实现前缀树。
+
 <!-- tabs:start -->
 
 ### **Python3**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```python
+class Trie:
+    def __init__(self):
+        self.name = None
+        self.isFile = False
+        self.content = []
+        self.children = {}
+
+    def insert(self, path, isFile):
+        node = self
+        ps = path.split('/')
+        for p in ps[1:]:
+            if p not in node.children:
+                node.children[p] = Trie()
+            node = node.children[p]
+        node.isFile = isFile
+        if isFile:
+            node.name = ps[-1]
+        return node
+
+    def search(self, path):
+        node = self
+        if path == '/':
+            return node
+        ps = path.split('/')
+        for p in ps[1:]:
+            if p not in node.children:
+                return None
+            node = node.children[p]
+        return node
+
+
+class FileSystem:
+
+    def __init__(self):
+        self.root = Trie()
+
+    def ls(self, path: str) -> List[str]:
+        node = self.root.search(path)
+        if node is None:
+            return []
+        if node.isFile:
+            return [node.name]
+        return sorted(node.children.keys())
 
+    def mkdir(self, path: str) -> None:
+        self.root.insert(path, False)
+
+    def addContentToFile(self, filePath: str, content: str) -> None:
+        node = self.root.insert(filePath, True)
+        node.content.append(content)
+
+    def readContentFromFile(self, filePath: str) -> str:
+        node = self.root.search(filePath)
+        return ''.join(node.content)
+
+
+# Your FileSystem object will be instantiated and called as such:
+# obj = FileSystem()
+# param_1 = obj.ls(path)
+# obj.mkdir(path)
+# obj.addContentToFile(filePath,content)
+# param_4 = obj.readContentFromFile(filePath)
 ```
 
 ### **Java**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```java
+class Trie {
+    String name;
+    boolean isFile;
+    StringBuilder content = new StringBuilder();
+    Map<String, Trie> children = new HashMap<>();
+
+    Trie insert(String path, boolean isFile) {
+        Trie node = this;
+        String[] ps = path.split("/");
+        for (int i = 1; i < ps.length; ++i) {
+            String p = ps[i];
+            if (!node.children.containsKey(p)) {
+                node.children.put(p, new Trie());
+            }
+            node = node.children.get(p);
+        }
+        node.isFile = isFile;
+        if (isFile) {
+            node.name = ps[ps.length - 1];
+        }
+        return node;
+    }
+
+    Trie search(String path) {
+        Trie node = this;
+        String[] ps = path.split("/");
+        for (int i = 1; i < ps.length; ++i) {
+            String p = ps[i];
+            if (!node.children.containsKey(p)) {
+                return null;
+            }
+            node = node.children.get(p);
+        }
+        return node;
+    }
+}
+
+class FileSystem {
+    private Trie root = new Trie();
+
+    public FileSystem() {
+
+    }
+    
+    public List<String> ls(String path) {
+        List<String> ans = new ArrayList<>();
+        Trie node = root.search(path);
+        if (node == null) {
+            return ans;
+        }
+        if (node.isFile) {
+            ans.add(node.name);
+            return ans;
+        }
+        for (String v : node.children.keySet()) {
+            ans.add(v);
+        }
+        Collections.sort(ans);
+        return ans;
+    }
+    
+    public void mkdir(String path) {
+        root.insert(path, false);
+    }
+    
+    public void addContentToFile(String filePath, String content) {
+        Trie node = root.insert(filePath, true);
+        node.content.append(content);
+    }
+    
+    public String readContentFromFile(String filePath) {
+        Trie node = root.search(filePath);
+        return node.content.toString();
+    }
+}
+
+/**
+ * Your FileSystem object will be instantiated and called as such:
+ * FileSystem obj = new FileSystem();
+ * List<String> param_1 = obj.ls(path);
+ * obj.mkdir(path);
+ * obj.addContentToFile(filePath,content);
+ * String param_4 = obj.readContentFromFile(filePath);
+ */
+```
+
+### **Go**
+
+```go
+type Trie struct {
+	name     string
+	isFile   bool
+	content  strings.Builder
+	children map[string]*Trie
+}
+
+func newTrie() *Trie {
+	m := map[string]*Trie{}
+	return &Trie{children: m}
+}
+
+func (this *Trie) insert(path string, isFile bool) *Trie {
+	node := this
+	ps := strings.Split(path, "/")
+	for _, p := range ps[1:] {
+		if _, ok := node.children[p]; !ok {
+			node.children[p] = newTrie()
+		}
+		node, _ = node.children[p]
+	}
+	node.isFile = isFile
+	if isFile {
+		node.name = ps[len(ps)-1]
+	}
+	return node
+}
+
+func (this *Trie) search(path string) *Trie {
+	if path == "/" {
+		return this
+	}
+	node := this
+	ps := strings.Split(path, "/")
+	for _, p := range ps[1:] {
+		if _, ok := node.children[p]; !ok {
+			return nil
+		}
+		node, _ = node.children[p]
+	}
+	return node
+}
+
+type FileSystem struct {
+	root *Trie
+}
+
+func Constructor() FileSystem {
+	root := newTrie()
+	return FileSystem{root}
+}
+
+func (this *FileSystem) Ls(path string) []string {
+	var ans []string
+	node := this.root.search(path)
+	if node == nil {
+		return ans
+	}
+	if node.isFile {
+		ans = append(ans, node.name)
+		return ans
+	}
+	for v := range node.children {
+		ans = append(ans, v)
+	}
+	sort.Strings(ans)
+	return ans
+}
+
+func (this *FileSystem) Mkdir(path string) {
+	this.root.insert(path, false)
+}
+
+func (this *FileSystem) AddContentToFile(filePath string, content string) {
+	node := this.root.insert(filePath, true)
+	node.content.WriteString(content)
+}
+
+func (this *FileSystem) ReadContentFromFile(filePath string) string {
+	node := this.root.search(filePath)
+	return node.content.String()
+}
 
+/**
+ * Your FileSystem object will be instantiated and called as such:
+ * obj := Constructor();
+ * param_1 := obj.Ls(path);
+ * obj.Mkdir(path);
+ * obj.AddContentToFile(filePath,content);
+ * param_4 := obj.ReadContentFromFile(filePath);
+ */
 ```
 
 ### **...**