Serialize and Deserialize BST

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 link to be reconstructed later in the same or another computer environment.

Design an algorithm to serialize and deserialize a binary search tree. There is no restriction on how your serialization/deserialization algorithm should work. You just need to ensure that a binary search tree can be serialized to a string and this string can be deserialized to the original tree structure.

The encoded string should be as compact as possible.

Note: Do not use class member/global/static variables to store states. Your serialize and deserialize algorithms should be stateless.

public class Codec {
    public String serialize(TreeNode root) {
        StringBuilder sb = new StringBuilder();
        serialize(root, sb);
        return sb.toString();
    }
    
    public void serialize(TreeNode root, StringBuilder sb) {
        if (root == null) return;
        sb.append(root.val).append(",");
        serialize(root.left, sb);
        serialize(root.right, sb);
    }

    // Decodes your encoded data to tree.
    public TreeNode deserialize(String data) {
        if (data.isEmpty()) return null;
        int[] treeData = convertToIntArray(data.split(","));
        return deserialize(treeData, 0, treeData.length - 1);
    }
    
    public TreeNode deserialize(int[] treeData, int start, int end) {
        if (start > end) return null;
        if (start == end) return new TreeNode(treeData[start]);
        
        TreeNode root = new TreeNode(treeData[start]);
        int breakPoint = findBreakPoint(treeData, start + 1, end, treeData[start]);
        root.left = deserialize(treeData, start + 1, breakPoint);
        root.right = deserialize(treeData, breakPoint + 1, end);
        return root;
    }
    
    private int findBreakPoint(int[] treeData, int start, int end, int target) {
        for (int i = start; i <= end; i++) {
            if (treeData[i] > target) {
                return i - 1;
            }
        }
        return end;
    }
    
    private int[] convertToIntArray(String[] input) {
        int[] intArray = new int[input.length];
        for (int i = 0; i < input.length; i++) {
            intArray[i] = Integer.parseInt(input[i]);
        }
        return intArray;
    }
}