2751_수 정렬하기2 (JAVA)

 

2751번: 수 정렬하기 2

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Collections;

public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();

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

		List<Integer> list = new ArrayList<>();

		for(int i=0; i<N; i++){
			list.add(Integer.parseInt(br.readLine()));
		}

		Collections.sort(list);

		for(int i=0; i<N; i++){
			sb.append(list.get(i)).append('\n');
		}
		System.out.println(sb);
	}
}

 

 

Collections.sort()

 

  - "객체 정렬"

  - ArrayList, List, Vector 등에 사용됨

 

List<Integer> list = new ArrayList<>();
list.add(3); list.add(5); list.add(1); list.add(2);

Collections.sort(list); // 출력 결과 : 1,2,3,5 

Collections.sort(list, Collections.reverseOrder()); // 출력 결과 : 5,3,2,1