GoalScope — serialize_bst (Qwen2.5-Coder-32B-Instruct) — hover a token to see the patched verbalization
<code>↵ def serialize_bst(root):↵ """Encodes a tree to a single string."""↵ def helper(node):↵ if not node:↵ return "null,"↵ return str(node.val) + "," + helper(node.left) + helper(node.right)↵ return helper(root)↵ ↵ class TreeNode:↵ def __init__(self, val=0, left=None, right=None):↵ self.val = val self.left = left self.right = right</code>