题目：
题解：
class Solution:
def deleteNode(self, root: Optional[TreeNode], key: int) -> Optional[TreeNode]:
cur, curParent = root, None
while cur and cur.val != key:
curParent = cur
cur = cur.left if cur.val > key else cur.right
if cur is None:
return root
if cur.left is None and cur.right is None:
cur = None
elif cur.right is None:
cur = cur.left
elif cur.left is None:
cur = cur.right
else:
successor, successorParent = cur.right, cur
while successor.left:
successorParent = successor
successor = successor.left
if successorParent.val == cur.val:
successorParent.right = successor.right
else:
successorParent.left = successor.right
successor.right = cur.right
successor.left = cur.left
cur = successor
if curParent is None:
return cur
if curParent.left and curParent.left.val == key:
curParent.left = cur
else:
curParent.right = cur
return root
