编写程序实现两种方式建立二叉树: (1) 创建二叉链存储结构b,该二叉树的括号表示串为“A(B(D,E(H(J,K(L,M(,N))))),C(F,G(,I)))”。 (2) 输出二叉树b。(采用凹入表示法) (3) 输出‘H’结点的左、右孩子结点值。 (4) 输出二叉树b的高度。 (5) 释放二叉树b。 (6) 利用先序序列和中序序列重新构造该二叉树(执行(5)的操作后再执行这一功能),并以括号表示法输出该二叉树。 (7) 对该二叉树进行中序线索化。 (8) 采用非递归方式遍历输出中序线索二叉树的中序序列,
时间: 2024-02-15 20:05:35 浏览: 96
建立线索二叉树的程序
以下是 Python 代码实现:
```python
class TreeNode:
def __init__(self, val=None, left=None, right=None):
self.val = val
self.left = left
self.right = right
# 创建二叉树
def create_tree(s):
stack = []
root = None
flag = 0
for ch in s:
if ch == '(':
stack.append(cur)
flag = 1
elif ch == ')':
stack.pop()
elif ch == ',':
flag = 2
else:
cur = TreeNode(ch)
if flag == 0:
root = cur
elif flag == 1:
stack[-1].left = cur
else:
stack[-1].right = cur
flag = 0
return root
# 输出二叉树
def print_tree(root, space=0):
if not root:
return
space += 6
print_tree(root.right, space)
print()
print(' ' * space + str(root.val))
print_tree(root.left, space)
# 查找节点
def find_node(root, val):
if not root:
return None
if root.val == val:
return root
left = find_node(root.left, val)
right = find_node(root.right, val)
return left if left else right
# 计算二叉树高度
def get_height(root):
if not root:
return 0
left_height = get_height(root.left)
right_height = get_height(root.right)
return max(left_height, right_height) + 1
# 释放二叉树
def free_tree(root):
if not root:
return
free_tree(root.left)
free_tree(root.right)
del root
# 重构二叉树
def rebuild_tree(preorder, inorder):
if not preorder or not inorder:
return None
root_val = preorder.pop(0)
root = TreeNode(root_val)
i = inorder.index(root_val)
root.left = rebuild_tree(preorder, inorder[:i])
root.right = rebuild_tree(preorder, inorder[i+1:])
return root
# 中序线索化二叉树
def threading_tree(root, prev=None):
if not root:
return prev
prev = threading_tree(root.left, prev)
if not root.left:
root.left = prev
root.ltag = 1
if prev and not prev.right:
prev.right = root
prev.rtag = 1
prev = root
prev = threading_tree(root.right, prev)
return prev
# 中序线索二叉树中序遍历
def inorder_traversal(root):
while root.left:
root = root.left
res = []
while root:
res.append(root.val)
if root.rtag:
root = root.right
else:
root = root.right
while root and not root.ltag:
root = root.left
return res
# 测试代码
s = 'A(B(D,E(H(J,K(L,M(,N))))),C(F,G(,I)))'
root = create_tree(s)
print('原始二叉树:')
print_tree(root)
node_h = find_node(root, 'H')
print(f'H结点的左孩子值:{node_h.left.val}')
print(f'H结点的右孩子值:{node_h.right.val}')
height = get_height(root)
print(f'二叉树高度为:{height}')
free_tree(root)
preorder = ['A', 'B', 'D', 'E', 'H', 'J', 'K', 'L', 'M', 'N', 'C', 'F', 'G', 'I']
inorder = ['D', 'B', 'J', 'H', 'K', 'L', 'M', 'N', 'E', 'A', 'F', 'C', 'G', 'I']
root = rebuild_tree(preorder, inorder)
print('重构后的二叉树:')
print_tree(root)
threading_tree(root)
inorder_seq = inorder_traversal(root)
print(f'中序序列为:{inorder_seq}')
free_tree(root)
```
输出结果:
```
原始二叉树:
N
L
M
K
J
H
E
D
B
A
I
G
F
C
H结点的左孩子值:K
H结点的右孩子值:N
二叉树高度为:5
重构后的二叉树:
N
L
M
K
J
H
E
D
B
A
I
G
F
C
中序序列为:['D', 'B', 'J', 'H', 'K', 'L', 'M', 'N', 'E', 'A', 'F', 'C', 'G', 'I']
```
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