class Solution:
    def createBinaryTree(
        self, descriptions: List[List[int]]
    ) -> Optional[TreeNode]:
        node_map = {}
        children = set()
        
        for description in descriptions:
            parent_value = description[0]
            child_value = description[1]
            is_left = bool(description[2])
            
            if parent_value not in node_map:
                node_map[parent_value] = TreeNode(parent_value)
            if child_value not in node_map:
                node_map[child_value] = TreeNode(child_value)
                
            if is_left:
                node_map[parent_value].left = node_map[child_value]
            else:
                node_map[parent_value].right = node_map[child_value]
                
            children.add(child_value)
            
        for node in node_map.values():
            if node.val not in children:
                return node
        return None