[Baekjoon Online Judge] 15654 - N과 M (5) / Java

https://www.acmicpc.net/problem/15654

15654번: N과 M (5)

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.StringTokenizer;

public class Main {

	static int N, M;
	static int[] num, isSelected;
	static StringBuilder sb = new StringBuilder();

	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());

		N = Integer.parseInt(st.nextToken());
		M = Integer.parseInt(st.nextToken());
		num = new int[N];
		isSelected = new int[N];

		st = new StringTokenizer(br.readLine());
		for (int i = 0; i < N; i++) {
			num[i] = Integer.parseInt(st.nextToken());
		}

		Arrays.sort(num);

		search(0, 0);
		System.out.println(sb);
	}

	private static void search(int cnt, int flag) {
		if (cnt == M) {
			for (int i = 0; i < M; i++) {
				sb.append(isSelected[i]).append(" ");
			}
			sb.append("\n");
			return;
		}

		for (int i = 0; i < N; i++) {
			if ((flag & (1 << i)) != 0) {
				continue;
			}

			isSelected[cnt] = num[i];
			search(cnt + 1, flag | (1 << i));
		}
	}
}