MeetingRooms.java

package com.freetymekiyan.algorithms.level.easy;

import java.util.Arrays;

/**
 * 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.
 * <p>
 * For example,
 * Given [[0, 30],[5, 10],[15, 20]],
 * return false.
 * <p>
 * Company Tags: Facebook
 * Tags: Sort
 * Similar Problems: (H) Merge Intervals, (M) Meeting Rooms II
 */
public class MeetingRooms {

    /**
     * Sort.
     * The actual problem is detecting whether there is any overlap between meetings.
     * Sort the intervals.
     * From second interval, check each interval with the previous one.
     * If current interval's start < previous interval's end, return false.
     */
    public boolean canAttendMeetings(Interval[] intervals) {
        Arrays.sort(intervals, (i1, i2) -> i1.start - i2.start);
        for (int i = 1; i < intervals.length; i++) {
            if (intervals[i].start < intervals[i - 1].end) {
                return false;
            }
        }
        return true;
    }

    public class Interval {

        int start;
        int end;

        Interval() {
            start = 0;
            end = 0;
        }

        Interval(int s, int e) {
            start = s;
            end = e;
        }
    }

}