Serialization

Serialization is the process of converting a data structure, like a binary tree, into a format that can be stored (e.g., in a file) or transmitted (e.g., over a network) and then reconstructed later. Deserialization is the reverse process of rebuilding the data structure from its serialized format. For a binary tree, a common way to serialize it is to convert it into a string. The key is to choose a traversal method and a way to represent null nodes. A preorder traversal is a good choice for this. During a preorder traversal, we append the current node's value to our string, followed by a delimiter. If a node is null, we append a special marker (like '#' or 'null'). For example, the tree with root 1, left child 2, and right child 3 would be serialized as "1,2,#,#,3,#,#,". The '#' markers are crucial for correctly identifying where subtrees end. To deserialize this string, we can use a recursive helper function or a queue. We read the values from the string one by one. The first value becomes the root. Then we recursively call the deserialize function to build its left subtree, and after that, its right subtree. The function knows it has finished building a subtree when it encounters the null markers.