题目
Given the root of a binary tree, the depth of each node is the shortest distance to the root.
Return the smallest subtree such that it contains all the deepest nodes in the original tree.
A node is called the deepest if it has the largest depth possible among any node in the entire tree.
The subtree of a node is tree consisting of that node, plus the set of all descendants of that node.
Note: This question is the same as 1123: https://leetcode.com/problems/lowest-common-ancestor-of-deepest-leaves/
解题思路
dfs，返回当前子树的哪个最深节点包含所有叶节点以及该子树的高度，如果两个子树高度相同，返回跟节点，否则返回较深子树的结果
代码
class Solution:
def subtreeWithAllDeepest(self, root: TreeNode) -> TreeNode:
def dfs(root):
if not root:
return (None, 0)
l = dfs(root.left)
r = dfs(root.right)
depth = max(l[1], r[1]) + 1
if l[1] < r[1]:
return (r[0], depth)
elif l[1] > r[1]:
return (l[0], depth)
return (root, depth)
return dfs(root)[0]
