1353最多可以参加的会议数目

class Solution {
public:
    int maxEvents(vector<vector<int>>& events) {
        map<int, vector<int>> vec;
        int maxD = 0;
        for (auto event : events) {
            if (event[1] > maxD) maxD = event[1];
            vec[event[0]].push_back(event[1]);
        }
        priority_queue<int, vector<int>, greater<int>> pri_que;
        int ans = 0;
        for (int i = 1; i <= maxD; i++) {
            while (!pri_que.empty() && pri_que.top() < i) pri_que.pop();
            for (auto day : vec[i]) {
                pri_que.push(day);
            }
            if (!pri_que.empty()) {
                ans++;
                pri_que.pop();
            }
        }
        return ans;
    }
};