二叉樹的構造
class
node
(object):
"""節點類"""
def__init__
(self, value=
none
, left=
none
, right=
none):
self.value = value
self.left = left
self.right = right
class
tree
(object):
"""二叉樹類"""
def__init__
(self)
:"""初始化樹類的根節點和遍歷佇列"""
self.root = node(
) self.tree_queue =
# 葉子結點的資料
defadd
(self, value)
:"""新增資料建構函式"""
node = node(value)
if self.root.value is
none
:# 樹為空則進行節點的新增
self.root = node
else
: cur_node = self.tree_queue[0]
# 獲取當前的根節點
if cur_node.left is
none
:# 左子樹為空則進行新增
cur_node.left = node
else
:# 有字數為空則加入
cur_node.right = node
self.tree_queue.pop(0)
# 當前節點分配完成，退出佇列
defmain()
: tree = tree(
) tree.add(0)
tree.add(1)
tree.add(2)
tree.add(3)
tree.add(4)
tree.add(5)
tree.add(6)
tree.add(7)
tree.add(8)
tree.add(9)
return tree
if __name__ ==
'__main__'
: tree = main(
)print
(tree)
import 二叉樹的構造 as tree_con
defpre_order
(root)
:"""遞迴實現樹的前序遍歷"""
if root is
none
:return
print
(root.value, end=
"\t"
) pre_order(root.left)
pre_order(root.right)
defpre_order_stack
(root)
:"""非遞迴實現樹的前序遍歷"""
if root is
none
:return
cur_node = root
pre_stack =
while pre_stack or cur_node:
while cur_node:
print
(cur_node.value, end=
"\t"
) cur_node = cur_node.left
cur_node = pre_stack.pop(
) cur_node = cur_node.right
print()
if __name__ ==
'__main__'
: tree = tree_con.main(
)print
(tree)
# pre_order(tree.root)
pre_order_stack(tree.root)
import 二叉樹的構造 as tree_con
defin_order
(root)
:"""遞迴實現樹的中序遍歷"""
if root is
none
:return
in_order(root.left)
print
(root.value, end=
"\t"
) in_order(root.right)
defin_order_stack
(root)
:"""非遞迴實現樹的中序遍歷"""
if root is
none
:return
cur_node = root
in_stack =
while in_stack or cur_node:
while cur_node:
cur_node = cur_node.left
cur_node = in_stack.pop(
)print
(cur_node.value, end=
"\t"
) cur_node = cur_node.right
print()
if __name__ ==
'__main__'
: tree = tree_con.main(
)print
(tree)
print
([ele.value for ele in tree.tree_queue]
) in_order_stack(tree.root)
in_order(tree.root)
import 二叉樹的構造 as tree_con
defpost_order
(root)
:"""遞迴實現樹的後序遍歷"""
if root is
none
:return
post_order(root.left)
post_order(root.right)
print
(root.value, end=
"\t"
)def
post_order_stack
(root)
:"""非遞迴實現樹的後序遍歷"""
if root is
none
:return
cur_node = root
post_stack1 =
post_stack2 =
while post_stack1:
cur_node = post_stack1.pop(
)if cur_node.left:
if cur_node.right:
while post_stack2:
print
(post_stack2.pop(
).value, end=
"\t"
)print()
defpost_order
(root):if
not root:
return
none
stack =
[root]
last =
none
while stack:
while stack[-1
].left:-1
].left)
while stack:
if stack[-1
].right == last or
not stack[-1
].right:
last = stack.pop(
)print
(last.val)
elif stack[-1
].right:-1
].right)
if __name__ ==
'__main__'
: tree = tree_con.main(
)print
(tree)
# print([ele.value for ele in tree.tree_queue])
post_order_stack(tree.root)
post_order(tree.root)
import 二叉樹的構造 as tree_con
deflevel_order
(root)
:if root is
none
:return
level_queue =
[root]
while level_queue:
cur_node = level_queue.pop(0)
print
(cur_node.value, end=
"\t"
)if cur_node.left:
if cur_node.right:
print()
if __name__ ==
'__main__'
: tree = tree_con.main(
)print
(tree)
level_order(tree.root)
專案二 二叉樹遍歷的遞迴思想
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