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Serialize and Deserialize Binary Tree

Certification: Advanced Level Accuracy: 100% Submissions: 1 Points: 15

Write a Java program to serialize and deserialize a binary tree. Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connection to be reconstructed later. In this problem, you need to design an algorithm to serialize a binary tree into a string and deserialize that string back into the original tree structure.

Example 1
    
  
  • Input: root = [1,2,3,null,null,4,5]
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  • Output: [1,2,3,null,null,4,5]
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  • Explanation: The tree looks like:


    Serialize and Deserialize Binary Tree with root node 1


    • Using preorder traversal, we can serialize this as "1,2,#,#,3,4,#,#,5,#,#". When we deserialize this string, we should get back the original tree structure.
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Example 2
    
  
  • Input: root = []
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  • Output: []
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  • Explanation: We need to serialize an empty tree. The empty tree can be represented as an empty string or a special marker. When we deserialize this, we should get back an empty tree.
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Constraints
    
  
  • The number of nodes in the tree is in the range [0, 10^4]
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  • -1000 ≤ Node.val ≤ 1000
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  • Time Complexity: O(n) for both serialization and deserialization, where n is the number of nodes
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  • Space Complexity: O(n)
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Binary TreePhillipsOracle
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Hint
Solution

Solution Hints

    
  
  • Use a recursive approach for both serialization and deserialization
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  • For serialization, consider using preorder traversal (root, left, right)
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  • Use a special marker (like "#" or "null") to denote null nodes
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  • For deserialization, process the serialized data in the same order as it was created
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  • Consider using a queue or other data structure to help process the serialized string
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  • Make sure to handle edge cases like an empty tree
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Steps to solve by this approach:

 Step 1: Define constants for null node representation and delimiter to separate values in the serialized string.

 Step 2: For serialization, use a recursive preorder traversal approach (root, left, right).

 Step 3: Append each node's value to a StringBuilder, followed by the delimiter. For null nodes, append the null symbol.

 Step 4: For deserialization, split the input string by the delimiter to get individual values.

 Step 5: Use a queue to process these values in the order they were serialized.

 Step 6: Recursively build the tree: create a node with the current value, then recursively build its left and right subtrees.

 Step 7: Handle edge cases like empty trees by checking for null or empty input string.

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