#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main()
{
    int n = 0;
	cin >> n;
	vector<int> a;
	for(int i = 0; i < n; ++ i) a.push_back(i + 1);
	do
	{
		for(int i = 0; i < n; ++ i) cout << a[i] << ' ';
		
		cout << endl;
	}while(next_permutation(a.begin(), a.end()));
  
    return 0;
}

#include<iostream>
using namespace std;
const int N = 10;
int st[N], path[N];//st表示每个数字状态
int n;
void dfs(int u)
{
    if (u > n)
    {
        for (int i = 1; i <= n; ++ i) cout << path[i] << ' ';
        cout << endl;
    }
    for (int i = 1; i <= n; ++ i)
    {
        if (!st[i])
        {
            path[u] = i;
            st[i] = 1;
            dfs(u + 1);
            st[i] = 0;
        }
    }
}
int main()
{
    cin >> n;
    dfs(1);
    return 0;
}

参考答案：

#include <iostream>

using namespace std;

const int N = 10;

int n;
int path[N];

void dfs(int u, int state)
{
    if (u == n)
    {
        for (int i = 0; i < n; i ++ ) printf("%d ", path[i]);
        puts("");

        return;
    }

    for (int i = 0; i < n; i ++ )
        if (!(state >> i & 1))
        {
            path[u] = i + 1;
            dfs(u + 1, state + (1 << i));
        }
}

int main()
{
    scanf("%d", &n);

    dfs(0, 0);

    return 0;
}