순열 출력

 

1.10이하의 N개 자연수가 주어지면 이중 M개를 뽑아 일렬로 나열하는 방법모두 출력

class Main {

	static int m, n;				

	public void DFS( int level , int [] perm, int[] ch,int []arr) {
		if( level == m ) {
			for ( int x : perm)
				System.out.print(x+" ");
			System.out.println();
			return;
		}else {
			for ( int i = 0 ; i < n ; i ++) {
				//중복 체크
				if( ch[i] == 0 ) {
					ch[i]=1;
					perm[level] = arr[i];//D1,D2,D3 3, 6 ,9
					DFS(level+1, perm, ch, arr);
					ch[i]=0;
				}
			}
		}
		
	}
	
	public static void main(String args[]) throws Exception {
		Main M = new Main();
		Scanner in = new Scanner(System.in);
		n = in.nextInt();
		m = in.nextInt();
		int arr[] = new int[n];
		int ch[] = new int[n];//중복확인용
		int perm[] = new int[m];
		for ( int i = 0 ; i < n ; i++)
			arr[i] = in.nextInt();
		
		//from level 0
		M.DFS(0, perm, ch ,arr);		
	}

}
ex)
input
3 2 
3 6 9

output
3 6 
3 9 
6 3 
6 9 
9 3 
9 6