#1 WA，#2 AC，#3#4#5 TLE

#include <bits/stdc++.h>
using namespace std;

const int N = 25+10;
int n, m;
bool vis[N];
int num[N];

void dfs(int x) {
	if(x > m) {
		for(int i = 1; i <= m; i++) cout << num[i] << ' ';
		cout << endl;
		return;
	}
	for(int i = 1; i <= n; i++) {
		if(vis[i] == true) continue;
		num[x] = i;
		vis[i] = true;
		dfs(x+1);
		vis[i] = false;
	}
}

int main() {
	cin >> n >> m;
	dfs(1);
	
	return 0;
}

测试点在这

基本上跟这道题一样