def mid_ord(node: TreeNode) -> int:
nonlocal accu_sum
if node is None:
return
mid_ord(node.right)
accu_sum += node.val
node.val = accu_sum
mid_ord(node.left)
def mergeTrees(self, root1: TreeNode, root2: TreeNode) -> TreeNode:
if not root1 and not root2:
return None
new_tree = TreeNode(0)
n1 = root1 if root1 else TreeNode(0)
n2 = root2 if root2 else TreeNode(0)
new_tree.val = n1.val + n2.val
new_tree.left = self.mergeTrees(n1.left, n2.left)
new_tree.right = self.mergeTrees(n1.right, n2.right)
return new_tree
def deleteNode(self, root: TreeNode, key: int) -> TreeNode:
if not root:
return None
if root.val == key:
if not root.left:
return root.right
if not root.right:
return root.left
new_root = root.left
while new_root.right:
new_root = new_root.right
root.val, new_root.val = new_root.val, root.val
root.left = self.deleteNode(root.left, key)
elif root.val > key:
root.left = self.deleteNode(root.left, key)
else:
root.right = self.deleteNode(root.right, key)
return root
def deleteNode(self, root: TreeNode, key: int) -> TreeNode:
if not root:
return root
if root.val == key:
if not root.left:
return root.right
elif not root.right:
return root.left
else:
# Find successor
succ = root.right
while succ and succ.left:
succ = succ.left
root.val = succ.val
root.right = self.deleteNode(root.right, succ.val)
elif key < root.val:
root.left = self.deleteNode(root.left, key)
else:
root.right = self.deleteNode(root.right, key)
return root