3-way tree data structure where every node's left subtree has keys less than the node's key, every middle subtree has keys equal to the node's key, and every right subtree has keys greater than the node's key
3-way tree data structure where every node's left subtree has keys less than the node's key, every middle subtree has keys equal to the node's key, and every right subtree has keys greater than the node's key (en)