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class Solution {
public:
    int minMeetingRooms(vector<vector<int>>& intervals) {
        int res = 0;
        sort(intervals.begin(), intervals.end());
        priority_queue<int, vector<int>, greater<int>> pq;
        for (auto& interval : intervals) {
            while (!pq.empty()) {
                if (pq.top() > interval[0]) break;
                pq.pop();
            }
            pq.push(interval[1]);
            res = max(res, int(pq.size()));
        }
        return res;
    }
};