백준 15649 c++

#include <iostream>
#define MAX 9

using namespace std;

int input(int lower, int upper);
void dfs(int cnt);

int n, m;
int arr[MAX] = { 0, };
bool visited[MAX] = { 0, };

int main(void) 
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	//int n, m;

	n = input(1, 8);
	m = input(1, n);
	dfs(0);

	return 0;
}

int input(int lower, int upper)
{
	//cout << "input()" << endl;
	int A;

	while (1)
	{
		cin >> A;
		if (A >= lower && A <= upper)
		{
			break;
		}
		else
		{
			;
		}
	}

	return A;
}

void dfs(int cnt)
{
	if (cnt == m)
	{
		for (int i = 0; i < m; i++)
		{
			cout << arr[i] << " ";
		}
		cout << '\n';
		return;
	}
	for (int i = 1; i <= n; i++)
	{
		if (!visited[i])
		{
			visited[i] = true;
			arr[cnt] = i;
			dfs(cnt + 1);
			visited[i] = false;
		}
	}
}