[백준] 1931 회의실 배정 - Greedy / Java

• 문제 링크

1931번: 회의실 배정

 

• 풀이 과정

 

• 풀이 코드

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.Arrays;
import java.util.Comparator;
import java.util.StringTokenizer;

public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
		StringTokenizer st;

		int n = Integer.parseInt(br.readLine());

		int[][] t = new int[n][2];

		for (int i = 0; i < n; i++) {
			st = new StringTokenizer(br.readLine());
			t[i][0] = Integer.parseInt(st.nextToken());
			t[i][1] = Integer.parseInt(st.nextToken());

		}

		Arrays.sort(t, new Comparator<int[]>() {
			@Override
			public int compare(int[] o1, int[] o2) {
				if (o1[1] == o2[1]) {
					return o1[0] - o2[0];
				} else {
					return o1[1] - o2[1];
				}
			}
		});

		int cnt = 0;
		int prev = 0;
		for (int i = 0; i < n; i++) {
			if (prev <= t[i][0]) {
				prev = t[i][1];
				cnt += 1;
			}
		}

		bw.write(cnt + "\n");
		bw.flush();
	}

}