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920 · Meeting Rooms - LintCode

# Description

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.

(0,8),(8,10) is not conflict at 8

# Example

Example1

Input: intervals = [(0,30),(5,10),(15,20)]
Output: false
Explanation:
(0,30), (5,10) and (0,30),(15,20) will conflict
Example2

Input: intervals = [(5,8),(9,15)]
Output: true
Explanation:
Two times will not conflict

# Solution

  • 用 comparator
  • 前者 end time 要比 當前 start time 少
public class Solution {
    /**
     * @param intervals: an array of meeting time intervals
     * @return: if a person could attend all meetings
     */
    public boolean canAttendMeetings(List<Interval> intervals) {
        if (intervals == null || intervals.size() == 0) {
            return true;
        }
        Collections.sort(intervals, new Comparator<Interval>(){
            public int compare(Interval a, Interval b) {
                return a.start - b.start;
            }
        });
        
        for (int i = 0; i < intervals.size() - 1; i++) {
            
            if (intervals.get(i).end > intervals.get(i + 1).start) {
                return false;
            }
        }
        return true;
    }
}