MeetingRoom

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

Solution 1. ์‹œ์ž‘ ์‹œ๊ฐ„ ๊ธฐ์ค€์œผ๋กœ Sorting. 2. ์ด์ „์˜ ๋ > ๋‹ค์Œ์˜ ์‹œ์ž‘ Compare.

์˜์‚ฌ์ฝ”๋“œ->Java ์–ธ์–ด๋กœ ๊ตฌํ˜„

//Interval ํด๋ž˜์Šค ๊ตฌํ˜„
class Interval {
    int start;
    int end;
    //constructor(์ƒ์„ฑ์ž)๋กœ ์ดˆ๊ธฐํ™”
    Interval() {
        this.start = 0;
        this.end = 0;
    }
    Interval(int s, int e) {
        this.start = s;
        this.end = e;
    }
}
//Solution ์‹œ์ž‘
public class MeetingRoom {
    public static void main(String[] args) {
        MeetingRoom a = new MeetingRoom();
        Interval in1 = new Interval(0,30);
        Interval in2 = new Interval(10,15);
        Interval in3 = new Interval(20,25);
        
        Interval[] intervals = {in1,in2,in3};
        System.out.println(a.solve(intervals));
    }
    public boolean solve(Interval[] intervals) {
        if(intervals == null)
            return false;
        print(Intervals);
        //1.์‹œ์ž‘ ์‹œ๊ฐ„ ๊ธฐ์ค€์œผ๋กœ Sorting.
        Arrays.sort(intervals, Comp);
        //2.์ด์ „์˜ ๋ > ๋‹ค์Œ์˜ ์‹œ์ž‘ Compare.
        for(int i=1; i<intervals.length;i++) {
            if(intervals[i-1].end > intervals[i].start)
                return false;
        }
        return true;
    }
    Comparator<Interval> Comp = new Comparator<Interval>(){
        @Override
        public int compare(Interval o1, Interval o2) {
            return o1.start - o2.start;
        }
    };
    public void print(Interval[] intervals) {
        for(int i = 0; i<intervals.length; i++) {
            Interval in = intervals[i];
            System.out.println(in.start + "  " + in.end);
        }
        
    }
}

Java ๋ณต์Šต

Compartor์™€ Comparable - Comparable : ๊ธฐ๋ณธ ์ •๋ ฌ๊ธฐ์ค€์„ ๊ตฌํ˜„ํ•˜๋Š” ๋ฐ ์‚ฌ์šฉ - Comparator : ๊ธฐ๋ณธ ์ •๋ ฌ๊ธฐ์ค€ ์™ธ์— ๋‹ค๋ฅธ ๊ธฐ์ค€์œผ๋กœ ์ •๋ ฌํ•˜๊ณ ์ž ํ•  ๋•Œ ์‚ฌ์šฉ

  • ์˜ค๋ฆ„์ฐจ์ˆœ ์ •๋ ฌ 1. Comparator ์˜ค๋ฒ„๋ผ์ด๋“œ

Comparator<Interval> Comp = new Comparator<Interval>(){
    @Override
    public int compare(Interval o1, Interval o2) {
        return o1.start - o2.start;
    }
};

2. Comparator ์•ˆ์—์„œ ์›€์ง์ด๋Š” ๊ฒƒ์€ compareTo ๋ฉ”์†Œ๋“œ์ด๋‹ค.

//compareTo ์ž‘๋™์›๋ฆฌ ์ดํ•ด.์˜ค๋ฅธ์ชฝ์ด ํฌ๋ฉด -1
public void compareToTest() {
    Integer num = 5;
    System.out.println(num.compareTo(3));//1
    System.out.println(num.compareTo(5));//0
    System.out.println(num.compareTo(88));//-1
}

3. ๋žŒ๋‹ค์‹์„ ์ด์šฉํ•œ ์˜ค๋ฆ„์ฐจ์ˆœ ์ •๋ ฌ.

Arrays.sort(array, ๋žŒ๋‹ค์‹) ๋žŒ๋‹ค์‹ : (o1,o2)->o1.start-o2.start

Arrays.sort(intervals,(o1,o2)->o1.start-o2.start);

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