백준 15654번 N과 M (5) [ Java ]

15654번: N과 M (5)

백트레킹 연습을 위한 N과 M 시리즈!

import java.util.*;

public class Main {
    static int N, M;
    static int[] num;
    static int[] print;
    static boolean[] visited;
    static StringBuilder sb = new StringBuilder();

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        N = sc.nextInt();
        M = sc.nextInt();
        num = new int[N];
        visited = new boolean[N];
        print = new int[M];
        for (int i=0; i<N; i++) num[i] = sc.nextInt();
        Arrays.sort(num);
        bt(0, 0);
        System.out.print(sb);
    }
    static void bt(int depth, int start){
        if (depth == M){
            for (int i : print)
                sb.append(i+" ");
            sb.append("\n");
            return;
        }
        for (int i=0; i<N; i++){
            if (!visited[i]) {
                visited[i] = true;
                print[depth] = num[i];
                bt(depth + 1, i + 1);
                visited[i] = false;
            }
        }
    }
}