Code zum Drucken eines binären Suchbaums in Python
class BSTNode:
def __init__(self, key=None):
self.left = None
self.right = None
self.key = key
# Insert method can add a list of nodes to the BST
def insert(self, keyList):
for i in keyList:
self.insertKey(i)
# This insertKey
def insertKey(self, key):
if not self.key:
self.key = key
return
if self.key == key:
return
if key < self.key:
if self.left:
self.left.insertKey(key)
return
self.left = BSTNode(key)
return
if self.right:
self.right.insertKey(key)
return
self.right = BSTNode(key)
def display(self):
lines, *_ = self._display_aux()
for line in lines:
print(line)
def _display_aux(self):
"""Returns list of strings, width, height, and horizontal coordinate of the root."""
# No child.
if self.right is None and self.left is None:
line = '%s' % self.key
width = len(line)
height = 1
middle = width // 2
return [line], width, height, middle
# Only left child.
if self.right is None:
lines, n, p, x = self.left._display_aux()
s = '%s' % self.key
u = len(s)
first_line = (x + 1) * ' ' + (n - x - 1) * '_' + s
second_line = x * ' ' + '/' + (n - x - 1 + u) * ' '
shifted_lines = [line + u * ' ' for line in lines]
return [first_line, second_line] + shifted_lines, n + u, p + 2, n + u // 2
# Only right child.
if self.left is None:
lines, n, p, x = self.right._display_aux()
s = '%s' % self.key
u = len(s)
first_line = s + x * '_' + (n - x) * ' '
second_line = (u + x) * ' ' + '\\' + (n - x - 1) * ' '
shifted_lines = [u * ' ' + line for line in lines]
return [first_line, second_line] + shifted_lines, n + u, p + 2, u // 2
# Two children.
left, n, p, x = self.left._display_aux()
right, m, q, y = self.right._display_aux()
s = '%s' % self.key
u = len(s)
first_line = (x + 1) * ' ' + (n - x - 1) * '_' + s + y * '_' + (m - y) * ' '
second_line = x * ' ' + '/' + (n - x - 1 + u + y) * ' ' + '\\' + (m - y - 1) * ' '
if p < q:
left += [n * ' '] * (q - p)
elif q < p:
right += [m * ' '] * (p - q)
zipped_lines = zip(left, right)
lines = [first_line, second_line] + [a + u * ' ' + b for a, b in zipped_lines]
return lines, n + m + u, max(p, q) + 2, n + u // 2
#Inorder Walk
def inorder(self):
if self.left:
self.left.inorder()
print(self.key)
if self.right:
self.right.inorder()
a = BSTNode()
a.insert([5,7,4,3,5,1,3,6]) #inserting some random numbers in the form of list
a.inorder()
a.display()
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