I want to delete a whole binary tree but the first root cannot be deleted and remains. How could I fix the code below so that I can delete the whole binary tree including the root node?
class binary_tree:
def __init__(self, root) -> None:
self.root = root
self.left = None
self.right = None
def __str__(self):
return '<%s, %d, %s>' % (self.left, self.root, self.right)
def get_size(self):
size = 1
if self.left is not None:
size += self.left.get_size()
if self.right is not None:
size += self.right.get_size()
return size
def insert_left(root, data) -> None:
if root.left is None:
root.left = binary_tree(data)
else:
insert_left(root.left, data)
def insert_right(root, data) -> None:
if root.right is None:
root.right = binary_tree(data)
else:
insert_right(root.right, data)
def clear_tree(root):
if root:
root.left = clear_tree(root.left)
root.right = clear_tree(root.right)
print(f"deleting node left={root.left}, root={root.root}, right={root.right}")
del root
if __name__ == '__main__':
root = binary_tree(4)
insert_left(root, 2)
insert_right(root, 6)
insert_left(root.left, 1)
insert_right(root.left, 3)
insert_left(root.right, 5)
insert_right(root.right, 7)
print(root)
print(root.get_size())
clear_tree(root)
print(root.get_size())
print(root)
"""
4
/ \
2 6
/ \ / \
1 3 5 7
"""
I tried modifying the clear_tree method from
def clear_tree(root):
if root:
clear_tree(root.left)
clear_tree(root.right)
print(f"deleting node left={root.left}, root={root.root}, right={root.right}")
del root
to
def clear_tree(root):
if root:
root.left = clear_tree(root.left)
root.right = clear_tree(root.right)
print(f"deleting node left={root.left}, root={root.root}, right={root.right}")
del root
The former code did not delete any node in the tree, and the latter did except the root node. Thus the output looks like this;
<<<None, 1, None>, 2, <None, 3, None>>, 4, <<None, 5, None>, 6, <None, 7, None>>>
7
deleting node left=None, root=1, right=None
deleting node left=None, root=3, right=None
deleting node left=None, root=2, right=None
deleting node left=None, root=5, right=None
deleting node left=None, root=7, right=None
deleting node left=None, root=6, right=None
deleting node left=None, root=4, right=None
1
<None, 4, None>
which I expect to look like;
<<<None, 1, None>, 2, <None, 3, None>>, 4, <<None, 5, None>, 6, <None, 7, None>>>
7
deleting node left=None, root=1, right=None
deleting node left=None, root=3, right=None
deleting node left=None, root=2, right=None
deleting node left=None, root=5, right=None
deleting node left=None, root=7, right=None
deleting node left=None, root=6, right=None
deleting node left=None, root=4, right=None
0
<None, None, None> (<- I'm not sure about this. But the size should be 0)
