Python | Leetcode Python题解之第450题删除二叉搜索树中的节点-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