김지수

import java.io.*; // 백준 N과 M(1) public class NM1 { int n; int r; boolean[] checkList; int[] result; public NM1(int n, int r) { this.n = n; this.r = r; checkList = new boolean[n]; result = new int[r]; } public void permutation(BufferedWriter bw, int depth) throws IOException { if (depth == r) { for (int num : result) { bw.write(num + " "); } bw.write("\n"); } else { for (int i = 1; i <= n; i++) { if (checkList[i - 1] == true) continue; else { result[depth] = i; checkList[i - 1] = true; permutation(bw, depth + 1); checkList[i - 1] = false; } } } } public static void main(String[] args) throws IOException { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out)); String[] strs = br.readLine().split(" "); int n = Integer.parseInt(strs[0]); int r = Integer.parseInt(strs[1]); NM1 p = new NM1(n, r); p.permutation(bw, 0); bw.flush(); } }