[BOJ] 15652. N과 M(4)

import java.util.Scanner;

public class Main {
	static int arr[]=new int [8];
	static boolean c[]=new boolean[9];
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		int N=sc.nextInt();
		int M=sc.nextInt();
		go(0,N,M,1);
	}
	
	public static void go(int index,int N,int M,int start) {
		if(index==M) {
            StringBuilder sb=new StringBuilder();
			for (int i = 0; i < M; i++) {
				sb.append(arr[i]);
                sb.append(" ");
			}
			System.out.print(sb+"\n");
			return;
		}
		
		for(int i=start;i<=N;i++) {
			arr[index]=i;
			c[i]=true;
			go(index+1,N,M,i);
			c[i]=false;
		}
	}
}