## [253\. Meeting Rooms II](https://leetcode.com/problems/meeting-rooms-ii/)

Given an array of meeting time intervals `intervals` where `intervals[i] = [starti, endi]`, return _the minimum number of conference rooms required_.

**Example 1:**

**Input:** intervals = \[\[0,30\],\[5,10\],\[15,20\]\]
**Output:** 2

**Example 2:**

**Input:** intervals = \[\[7,10\],\[2,4\]\]
**Output:** 1

**Constraints:**

- `1 <= intervals.length <= 104`
- `0 <= starti < endi <= 106`

class Solution {
public:
    int minMeetingRooms(vector<vector<int>>& intervals) {
        int n = intervals.size();

        sort(intervals.begin(), intervals.end());
        priority_queue<int, vector<int>, greater<int>> minHeap;

        // #0: minHeap = [30];
        // #1: minHeap = [10, 30];
        // #2: minHeap = [10, 20];
        for (auto& interval : intervals) {
            if (!minHeap.empty() && interval[0] >= minHeap.top()) {
                minHeap.pop();
            }
            minHeap.push(interval[1]);
        }
        return minHeap.size();
    }
};

:::success
- 時間複雜度：$O(N \log N)$
- 空間複雜度：$O(N)$
:::