[BOJ] 15651. N과 M(3)

import java.util.Scanner;

public class Main {
	static int arr[]=new int [8];
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		int N=sc.nextInt();
		int M=sc.nextInt();
		go(0,N,M);
	}
	
	public static void go(int index,int N,int M) {
		if(index==M) {
            StringBuilder sb=new StringBuilder();
			for (int i = 0; i < M; i++) {
				sb.append(arr[i]);
                sb.append(" ");
			}
			System.out.print(sb+"\n");
			return;
		}
		
		for(int i=1;i<=N;i++) {
			arr[index]=i;
			go(index+1,N,M);
		}
	}
}

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int M = sc.nextInt();
		int arr[] = new int [M];
		
		System.out.println(go(N,M,0,arr));
	}
	
	public static StringBuilder go(int N, int M, int index, int[] arr) {		
		if(index == M) {		
			StringBuilder sb = new StringBuilder();
			for(int i = 0; i < M; i++) {
				sb.append(arr[i]);
				sb.append(" ");
			}
            sb.append("\n");
            
			return sb;
		}
		
		StringBuilder ans = new StringBuilder();
		for(int i = 1; i <= N; i++) {		
			arr[index] = i;
			ans.append(go(N, M, index + 1,arr));		
		}
		return ans;
		
	}
}