摘要：
并没有理解这种递归想法： class Solution: def __init__(self): self.ans=None def lowestCommonAncestor(self, root: 'TreeNode', p: 'TreeNode', q: 'TreeNode') -> 'Tree 阅读全文
摘要：
class Solution: def lowestCommonAncestor(self, root: 'TreeNode', p: 'TreeNode', q: 'TreeNode') -> 'TreeNode': if p.val>q.val: p,q=q,p if q.val<root.va 阅读全文
摘要：
暴力法： class Solution: def countNodes(self, root: TreeNode) -> int: if not root: return 0 else: return 1+self.countNodes(root.left)+self.countNodes(root 阅读全文
摘要：
class Solution: def invertTree(self, root: TreeNode) -> TreeNode: if not root: return root def helper(node): if node: if node.left or node.right: node 阅读全文