1 class TreeNode:
2 def __init__(self, val=0, left=None, right=None, parent=None):
3 self.val = val
4 self.left = left
5 self.right = right
6 self.parent = parent
7
8
9 def get_left_most(node):
10 if not node:
11 return node
12 while node.left:
13 node = node.left
14 return node
15
16 def get_successor_node(node):
17 if not node:
18 return node
19 # 如果有右树，则为右子树中最左的节点
20 if node.right:
21 return get_left_most(node.right)
22 else:
23 parent = node.parent
24 # 当前节点是其父节点的右孩子，当前节点可能为最右节点
25 while not parent and parent.left != node:
26 node = parent
27 parent = node.parent
28 return parent
