252. 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.

Example 1:

Input: [[0,30],[5,10],[15,20]]
Output: false

Example 2:

Input: [[7,10],[2,4]]
Output: true

// Sort
bool canAttendMeetings(vector<vector<int>>& intervals) { // time: O(nlogn); space: O(1)
    if (intervals.empty()) return true;
    sort(intervals.begin(), intervals.end());
    for (int i = 1; i < intervals.size(); ++i) {
        if (intervals[i - 1][1] > intervals[i][0]) return false;
    }
    return true;
}

253. Meeting Rooms II