백준 6603 로또 [ Java ]

6603번: 로또

import java.io.*;
import java.util.*;

public class Main {
    static int n;
    static int[] num = new int[6];
    static boolean[] visited;
    static int[] arr;
    static StringBuilder sb = new StringBuilder();
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        while (true){
            arr = Arrays.stream(br.readLine().split(" "))
                        .mapToInt(Integer::parseInt)
                        .toArray();
            n = arr[0];
            visited = new boolean[n+1];
            if (n == 0) {
                System.out.print(sb);
                System.exit(0);
            }
            bt(0, 1);
            sb.append("\n");
        }
    }
    static void bt(int depth, int start){
        if (depth == 6){
            Arrays.stream(num).forEach(i->sb.append(i+" "));
            sb.append("\n");
            return;
        }
        for (int i=start; i<=n; i++){
            if (!visited[i]){
                visited[i] = true;
                num[depth] = arr[i];
                bt(depth+1, i+1);
                visited[i] = false;
            }
        }
    }
}