BOJ1931 회의실 배정(R) 대표문제

https://www.acmicpc.net/problem/1931

1931번: 회의실 배정

 

import java.io.*;
import java.util.*;
public class Main
{   public static class Meeting{
    Integer start;
    Integer end;
    Meeting(Integer start, Integer end){
        this.start= start;
        this.end = end;
    }
}

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        
		int n = Integer.valueOf(br.readLine());
		Meeting[] meetings = new Meeting[n];
		
		for(int i=0; i<n;i++){
		    String[] input = br.readLine().split(" ");
		    meetings[i] = new Meeting(Integer.valueOf(input[0]),Integer.valueOf(input[1]));
		}

        Arrays.sort(meetings, (m1,m2) -> {
            if(m1.end==m2.end) return m1.start-m2.start;
            return m1.end-m2.end; 
        });
        
        
        int end=0;
        int count =0;
        for(int i=0; i<n;i++){
            if (meetings[i].start>=end){
                count++;
                end= meetings[i].end;
            }
        }
        
        bw.write(count+"");
		bw.flush();
	}
}