Merge pull request #404 from adityadmahale/main

Create 297-Serialize-and-Deserialize-Binary-Tree.java

Author: neetcode-gh

java/297-Serialize-and-Deserialize-Binary-Tree.java

@@ -0,0 +1,55 @@
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+public class Codec {
+    
+    private int i;
+
+    // Encodes a tree to a single string.
+    public String serialize(TreeNode root) {
+        List<String> list = new ArrayList<>();
+        serializeDFS(root, list);
+        
+        return String.join(",", list);
+    }
+    
+    private void serializeDFS(TreeNode root, List<String> list) {
+        if (root == null) {
+            list.add("N");
+            return;
+        }
+        list.add(String.valueOf(root.val));
+        serializeDFS(root.left, list);
+        serializeDFS(root.right, list);
+    }
+
+    // Decodes your encoded data to tree.
+    public TreeNode deserialize(String data) {
+        String[] tokens = data.split(",");
+        return deserializeDFS(tokens);
+    }
+    
+    private TreeNode deserializeDFS(String[] tokens) {
+        String token = tokens[this.i];
+        if (token.equals("N")) {
+            this.i++;
+            return null;
+        }
+        var node = new TreeNode(Integer.parseInt(token));
+        this.i++;
+        node.left = deserializeDFS(tokens);
+        node.right = deserializeDFS(tokens);
+        return node;
+    }
+}
+
+// Your Codec object will be instantiated and called as such:
+// Codec ser = new Codec();
+// Codec deser = new Codec();
+// TreeNode ans = deser.deserialize(ser.serialize(root));