3607. 电网维护

3607. 电网维护

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题目链接：3607. 电网维护

代码如下：

class Solution {
public:
	vector<int> processQueries(int c, vector<vector<int>>& connections, vector<vector<int>>& queries) {
		vector<vector<int>> g(c + 1);
		for (auto& e : connections) {
			int x = e[0], y = e[1];
			g[x].push_back(y);
			g[y].push_back(x);
		}

		vector<int> belong(c + 1, -1);//记录每个节点所属的连通块
		vector<priority_queue<int, vector<int>, greater<>>> heaps;
		priority_queue<int, vector<int>, greater<>> pq;

		auto dfs = [&](auto&& dfs, int x)->void {
			belong[x] = heaps.size();//记录节点x在哪个堆
			pq.push(x);
			for (int y : g[x]) {
				if (belong[y] < 0) {
					dfs(dfs,y);
				}
			}
		};

		for (int i = 1;i <= c;i++) {
			if (belong[i] < 0) {
				dfs(dfs, i);
				heaps.push_back(move(pq));
			}
		}

		vector<int> res;
		vector<int8_t> offline(c + 1);
		for (auto& q : queries) {
			int x = q[1];
			if (q[0] == 2) {
				offline[x] = true;
				continue;
			}
			if(!offline[x]) {
				res.push_back(x);
				continue;
			}
			auto& h = heaps[belong[x]];
			//懒删除：取堆顶的时候，如果离线，才删除
			while(!h.empty()&&offline[h.top()]) {
				h.pop();
			}
			res.push_back(h.empty() ? -1 : h.top());
		}
		return res;
	}
};