leetcode解题: Meeting Rooms (252)

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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.

解法1：O(NlogN) Time

考察的是对custom class排序的能力，我们只需要用标准的库函数，用上自己定义的比较函数就可以了。比较的时候后一个meeting的开始时间不能早于前一个会议的结束时间。
C++

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/**
 * Definition for an interval.
 * struct Interval {
 *     int start;
 *     int end;
 *     Interval() : start(0), end(0) {}
 *     Interval(int s, int e) : start(s), end(e) {}
 * };
 */
bool compare(Interval left, Interval right) {
        return left.start < right.start;
}
class Solution {
public:
    bool canAttendMeetings(vector<Interval>& intervals) {
        std::sort(intervals.begin(), intervals.end(), compare);
        for (int i = 1; i < intervals.size(); i++) {
            if (intervals[i].start < intervals[i - 1].end) {
                return false;
            }
        }
        return true;
    }
};

Java

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