Leetcode 2925. Maximum Score After Applying Operations on a Tree

• Leetcode 2925. Maximum Score After Applying Operations on a Tree
  • 1. 解题思路
  • 2. 代码实现

• 题目链接：2925. Maximum Score After Applying Operations on a Tree

1. 解题思路

这一题思路上来说还是很直接的，就是用一个深度优先遍历即可，标记一下每一条路径之前有没有保留过节点，然后找出最大方案即可。

2. 代码实现

给出python代码实现如下：

class Solution:
    def maximumScoreAfterOperations(self, edges: List[List[int]], values: List[int]) -> int:
        graph = defaultdict(list)
        for u, v in edges:
            graph[u].append(v)
            graph[v].append(u)
            
        @lru_cache(None)
        def dfs(u, p, have_point):
            if have_point:
                ans = values[u]
                for v in graph[u]:
                    if v == p:
                        continue
                    ans += dfs(v, u, True)
                return ans
            else:
                if len(graph[u]) == 1 and p != -1:
                    return 0
                ans1, ans2 = 0, values[u]
                for v in graph[u]:
                    if v == p:
                        continue
                    ans1 += dfs(v, u, True)
                    ans2 += dfs(v, u, False)
                return max(ans1, ans2)
        
        return dfs(0, -1, False)

提交代码评测得到：耗时1316ms，占用内存57.8MB。