kingsubin

import java.io.*;
import java.util.*;
 
public class boj_15663 {
    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
    static StringTokenizer st;
    static boolean[] v = new boolean[10];
    static int[] a = new int[10];
    static int[] val;
    static int n, m;
 
    public static void main(String[] args) throws IOException {
        st = new StringTokenizer(br.readLine());
        n = Integer.parseInt(st.nextToken());
        m = Integer.parseInt(st.nextToken());
        val = new int[n];
 
        st = new StringTokenizer(br.readLine());
        for (int i = 0; i < n; i++) {
            val[i] = Integer.parseInt(st.nextToken());
        }
 
        Arrays.sort(val);
 
        func(0);
        bw.flush();
        bw.close();
    }
 
    static void func(int k) throws IOException {
        if (k == m) {
            for (int i = 0; i < m; i++) {
                bw.append(a[i] + " ");
            }
            bw.newLine();
            return;
        }
 
        int before = 0;
        for (int i = 0; i < n; i++) {
            if (v[i]) continue;
            if (i != 0 && before == val[i]) continue;
 
            before = val[i];
 
            a[k] = val[i];
            v[i] = true;
 
            func(k + 1);
            v[i] = false;
        }
    }
 
 
}
 

 

- 백트래킹

 

- 중복값 처리를 해줘야해서 따로 변수 before을 만듬

- 매번 before 초기화 해주고 같으면 continue;

 

 

 

 

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www.acmicpc.net/problem/15663