3373. 连接两棵树后最大目标节点数目 II

3373. 连接两棵树后最大目标节点数目 II

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题目链接：3373. 连接两棵树后最大目标节点数目 II

代码如下：

class Solution {
public:
	vector<int> maxTargetNodes(vector<vector<int>>& edges1, vector<vector<int>>& edges2) {
		auto count = [](vector<vector<int>>& edges) {
			vector<vector<int>> g(edges.size() + 1);
			for (auto& e : edges) {
				int x = e[0], y = e[1];
				g[x].push_back(y);
				g[y].push_back(x);
			}

			array<int, 2> cnt{};
			auto dfs = [&](auto&& dfs, int x, int fa, int d)->void {
				cnt[d]++;
				for (int y : g[x]) {
					if (y != fa) {
						dfs(dfs, y, x, d ^ 1);
					}
				}
				};

			dfs(dfs, 0, -1, 0);
			return pair(g, cnt);
			};

		auto [_, cnt2] = count(edges2);
		int max2 = max(cnt2[0], cnt2[1]);

		auto [g, cnt1] = count(edges1);
		vector<int> res(g.size(), max2);
		auto dfs = [&](auto&& dfs, int x, int fa, int d)->void {
			res[x] += cnt1[d];
			for (int y : g[x]) {
				if (y != fa) {
					dfs(dfs,y, x, d ^ 1);
				}
			}
			};
		dfs(dfs,0, -1, 0);
		return res;
	}

private:
	vector<vector<int>> buildTree(vector<vector<int>>& edges) {
		vector<vector<int>> g(edges.size() + 1);
		for (auto& e : edges) {
			int x = e[0], y = e[1];
			g[x].push_back(y);
			g[y].push_back(x);
		}
		return g;
	}
};