class Solution(object):
def is_balanced(self, root: TreeNode):
if not root:
return True
return self.traverse(root) != -1
def traverse(self, node):
if not node:
return 0
left = self.traverse(node.left)
if left == -1:
return -1
right = self.traverse(node.right)
if right == -1:
return -1
if abs(left - right) > 1:
return -1
return max(left, right) + 1
if __name__ == "__main__":
import sys
sys.path.append("..")
from playground.TreePlayground import BinaryTreeUtil
root = BinaryTreeUtil.build_tree([1, 1, 1, 1, 1, None, 1])
BinaryTreeUtil.pretty_print_tree(root)
soln = Solution()
print(soln.is_balanced(root))
elif node.left and node.right:
predecessor = self.pick_predecessor(node)
if node == parent.left:
parent.left = predecessor
else:
parent.right = predecessor
predecessor.right = node.right
if predecessor == node.left:
predecessor.left = node.left
def pick_predecessor(self, node):
parent = node
node = node.left
while node.right:
parent = node
node = node.right
if node == parent.left:
parent.left = None
else:
parent.right = None
print(parent.val, node.val)
return node
def get_root(self):
return self.root
bst = BinarySearchTree([1, 2, 3, 4, 7, 6, 5, 9, 8])
BinaryTreeUtil.pretty_print_tree(bst.get_root())
bst.delete_node(7)
BinaryTreeUtil.pretty_print_tree(bst.get_root())