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.

We can sort the intervals by the start time, if those intervals have no overlap, then the person could attend all meetings.

class Solution {
    public boolean canAttendMeetings(int[][] intervals) {
        if (intervals == null || intervals.length == 0) {
            return true;
        }
        Arrays.sort(intervals, (i1, i2) -> {
            return i1[0] - i2[0];
        });
        for (int i = 0; i < intervals.length; i++) {
            if (i + 1 < intervals.length && intervals[i][1] > intervals[i + 1][0]) {
                return false;
            }
        }
        return true;
    }
}