[LeetCode] Meeting Rooms I & II

Meeting Rooms

Given an array of meeting time intervals consisting of start and end times [[s1,e1],[s2,e2],...] (si < ei), determine if a person could attend all meetings.

For example,
Given [[0, 30],[5, 10],[15, 20]],
return false.

 /**
  * Definition for an interval.
  * struct Interval {
  *     int start;
  *     int end;
  *     Interval() : start(0), end(0) {}
  *     Interval(int s, int e) : start(s), end(e) {}
  * };
  */
 class Solution {
 public:
     bool canAttendMeetings(vector<Interval>& intervals) {
         sort(intervals.begin(), intervals.end(), [](const Interval &a, const Interval &b) {
             return a.start < b.start;
         });
         for (int i = ; i < intervals.size(); ++i) {
             if (intervals[i].start < intervals[i-].end) return false;
         }
         return true;
     }
 };

Meeting Rooms II

Given an array of meeting time intervals consisting of start and end times [[s1,e1],[s2,e2],...] (si < ei), find the minimum number of conference rooms required.

For example,
Given [[0, 30],[5, 10],[15, 20]],
return 2.

 /**
  * Definition for an interval.
  * struct Interval {
  *     int start;
  *     int end;
  *     Interval() : start(0), end(0) {}
  *     Interval(int s, int e) : start(s), end(e) {}
  * };
  */
 class Solution {
 public:
     int minMeetingRooms(vector<Interval>& intervals) {
         vector<pair<int, int>> schedule;
         for (auto interval : intervals) {
             schedule.push_back({interval.start, });
             schedule.push_back({interval.end, -});
         }
         sort(schedule.begin(), schedule.end());
         int cnt = , res = ;
         for (auto s : schedule) {
             if (s.second == ) ++cnt;
             else --cnt;
             res = max(res, cnt);
         }
         return res;
     }
 };