python二叉搜索树与双向链表转换实现方法

# encoding=utf8
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class binarytreenode():
def __init__(self, value, left = none, right = none):
self.value = value
self.left = left
self.right = right
def 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_10
def print_a_tree(root):
if root is none:return
print_a_tree(root.left)
print root.value, ‘ ‘,
print_a_tree(root.right)
while head is not none:
print head.value, ‘ ‘,
print ”
”’构造树的双向链表，返回这个双向链表的最左结点和最右结点的指针”’
if root is none:
return (none, none)
# 递归构造出左子树的双向链表
(l_1, r_1) = create_linked_list(root.left)
left_most = l_1 if l_1 is not none else root
(l_2, r_2) = create_linked_list(root.right)
right_most = r_2 if r_2 is not none else root
# 将整理好的左右子树和root连接起来
root.left = r_1
if r_1 is not none:r_1.right = root
root.right = l_2
if l_2 is not none:l_2.left = root
# 由于是双向链表，返回给上层最左边的结点和最右边的结点指针
return (left_most, right_most)
if __name__ == ‘__main__’:
tree_1 = create_a_tree()
print_a_tree(tree_1)
(left_most, right_most) = create_linked_list(tree_1)
pass

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