[Baekjoon Online Judge] 15652 - N과 M (4) / Java

https://www.acmicpc.net/problem/15652

15652번: N과 M (4)

import java.util.Scanner;

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

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		N = sc.nextInt();
		M = sc.nextInt();
		num = new int[N + 1];
		isSelected = new int[M];

		for (int i = 1; i <= N; i++) {
			num[i] = i;
		}

		search(0, 1);
		System.out.println(sb);
	}

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

		for (int i = start; i <= N; i++) {
			isSelected[cnt] = num[i];
			search(cnt + 1, i);
		}
	}
}