Serialize and Deserialize Binary Tree

Hard/SerializeandDeserializeBinaryTree.java

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+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+public class Codec {
+
+    // Encodes a tree to a single string.
+    public String serialize(TreeNode root) {
+        if(root == null){
+            return "X";
+        }
+        String leftSerialized = serialize(root.left);
+        String rightSerialized = serialize(root.right);
+        return root.val + ","+leftSerialized + ","+rightSerialized;
+    }
+
+    // Decodes your encoded data to tree.
+    public TreeNode deserialize(String data) {
+        Queue<String>  nodesLeft = new LinkedList<>();
+        nodesLeft.addAll(Arrays.asList(data.split(",")));
+        return deserializeHelper(nodesLeft);
+
+    }
+    public TreeNode deserializeHelper(Queue<String> nodesLeft){
+        String valueforNode = nodesLeft.poll();
+        if(valueforNode.equals("X")) return null;
+        TreeNode newNode = new TreeNode(Integer.valueOf(valueforNode));
+        newNode.left = deserializeHelper(nodesLeft);
+        newNode.right = deserializeHelper(nodesLeft);
+        return newNode;
+    }
+}