백준 15649번

원본 : www.acmicpc.net/problem/15649

15649번: N과 M (1)

 

풀이

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class Main {
	public static void main(String[] args) throws Exception {

		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));
		
        String str = reader.readLine();
        int n = Integer.parseInt(str.split(" ")[0]);
        int m = Integer.parseInt(str.split(" ")[1]);
        int arr[] = new int[n];
        int output[] = new int[m];
        boolean visited[] = new boolean[n];
        
        for (int i = 0; i < n; i++) {
            arr[i] = i + 1;
            visited[i] = false;
        }
        
        permutation(arr, output, visited, 0, n, m);
        
		writer.flush();
    }
    
    public static void permutation(int arr[], int output[], boolean visited[], int depth, int n, int r) throws Exception{
        
        if (depth < r) {
            for (int i = 0; i < n; i++) {
            if (visited[i] == false) {
                visited[i] = true;
                output[depth] = arr[i];
                permutation(arr, output, visited, depth + 1, n, r);
                visited[i] = false;
            }
        }
        } else {
            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));
            for (int i = 0; i < r; i++) {
                writer.write(output[i] + " ");
            }
            writer.newLine();
            writer.flush();
        }
        
        
    }
    
}