if root is None:
return
# 有节点，标记该节点深度
depth += 1
# 该节点为叶子节点
if root.left is None and root.right is None:
# 更新最大深度
self.depth = max(depth, self.depth)
return
if root.left:
self._dfs(root.left, depth)
if root.right:
self._dfs(root.right, depth)
def _maxDepth2(self, root):
# DFS
if root is None:
return 0
self._dfs(root, 0)
return self.depth
if __name__ == '__main__':
obj = Solution()
while True:
nums_str = input().strip().split()
nodes = [int(n) if n != 'null' else None for n in nums_str]
root = get_binary_tree(nodes)
res = obj._maxDepth2(root)
print(res)
"""
if root is None:
return None
# 1表示还没有弹出孩子，0表示已经弹出孩子，可以访问
stack = [(1, root)]
res = []
while stack:
state, node = stack.pop()
if state == 1:
stack.append((0, node)) # 访问完右子树后访问父节点
if node.right:
stack.append((1, node.right))
if node.left:
stack.append((1, node.left))
else:
res.append(node.val)
return res
if __name__ == '__main__':
obj = Solution()
while True:
node_list_str = input().strip().split()
node_list = [int(v) if v != 'null' else None for v in node_list_str]
root = get_binary_tree(node_list)
res = obj.postorderTraversal(root)
print(res)
