算法的重要性，我就不多说了吧，想去大厂，就必须要经过基础知识和业务逻辑面试+算法面试。所以，为了提高大家的算法能力，这个公众号后续每天带大家做一道算法题，题目就从LeetCode上面选 ！今天和大家聊的问题叫做 二叉树中的最大路径和，我们先来看题面：https:///problems/binary-tree-maximum-path-sum/Given a non-empty binary tree, find the maximum path sum.
For this problem, a path is defined as any node sequence from some starting node to any node in the tree along the parent-child connections. The path must contain at least one node and does not need to go through the root.
题意本题中，路径被定义为一条从树中任意节点出发，沿父节点-子节点连接，达到任意节点的序列。该路径至少包含一个节点，且不一定经过根节点。解题class Solution:
def maxPathSum(self, root: TreeNode) -> int:
def max_gain(node):
nonlocal max_sum
if not node:return 0
left_max = max(max_gain(node.left), 0)
right_max = max(max_gain(node.right),0)
new_price = node.val + left_max + right_max
max_sum = max(max_sum, new_price)
return node.val + max(left_max, right_max)
max_sum = float('-inf')
max_gain(root)
return max_sum 好了，今天的文章就到这里，如果觉得有所收获，请顺手点个在看或者转发吧，你们的支持是我最大的动力。
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