[백준] N과M(3)

중복 가능 : visit 배열이 필요 없다. 

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

public class Main {
	private static int[] arr;
	private static boolean[] visit;
	private static StringBuilder sb = new StringBuilder();

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

		String line = br.readLine();
		StringTokenizer st = new StringTokenizer(line);

		int n = Integer.parseInt(st.nextToken());
		int m = Integer.parseInt(st.nextToken());

		arr = new int[m];
		visit = new boolean[n];

		bt(n, m, 0);

		System.out.println(sb);

	}

	private static void bt(int n, int m, int depth) {
		if (depth == m) {
			for (int i : arr) {
				sb.append(i + " ");
			}
			sb.append("\n");
			return;
		}

		for (int i = 0; i < n; i++) {
			arr[depth] = i + 1;
			bt(n, m, depth + 1);
		}
	}
}