Python Binary Search Tree and two-way linked list conversion implementation method, python binary

Python Binary Search Tree and two-way linked list conversion implementation method, python binary

This article describes how to implement the Python Binary Search Tree and two-way linked list. We will share this with you for your reference. The details are as follows:

# Encoding = utf8''' question: enter a binary search tree and convert it into a sorted two-way linked list. It is required that no new node can be created, and only the point of the node pointer in the tree can be adjusted. '''Class BinaryTreeNode (): def _ init _ (self, value, left = None, right = None): self. value = value self. left = left self. right = rightdef create_a_tree (): node_4 = BinaryTreeNode (4) node_8 = BinaryTreeNode (8) node_6 = BinaryTreeNode (6, node_4, node_8) node_12 = BinaryTreeNode (12) node_16 = BinaryTreeNode (16) node_14 = BinaryTreeNode (14, node_12, node_16) node_10 = BinaryTreeNode (10, node_6, node_14) return node_10def print_a_tree (root): if root is None: return print_a_tree (root. left) print root. value, '', print_a_tree (root. right) def print_a_resource_list (head): print 'linked _ list: 'while head is not None: print head. value, '', head = head. right print ''def create_resource_list (root): ''' construct a two-way linked list of the tree. Return the leftmost node and rightmost node pointer ''' if root is None: return (None, None) # recursively construct the two-way linked list (l_1, r_1) = create_resource_list (root. left) left_most = l_1 if l_1 is not None else root (l_2, r_2) = create_1__list (root. right) right_most = r_2 if r_2 is not None else root # connect the left and right subtree with the root. left = r_1 if r_1 is not None: r_1.right = root. right = l_2 if l_2 is not None: l_2.left = root # as a two-way linked list, return to the leftmost node on the upper layer and rightmost node pointer return (left_most, right_most) if _ name _ = '_ main _': tree_1 = create_a_tree () print_a_tree (tree_1) (left_most, right_most) = create_pai_list (tree_1) alias (left_most) pass