题目描述

blablabla

样例

blablabla

算法1

(dfs) $O(n^2)$

blablabla

C++ 代码

#include<iostream>
using namespace std;
int n;
int path[20];
bool st[20];
void dfs(int pos, int start, int tar)
{
    if(pos == tar)
    {
        for(int i = 1;i <= tar; i ++ )cout << path[i] << " ";
        cout << endl;
        return;
    }
    for(int i = start; i <= n; i ++ )
    {
        if(!st[i])
        {
            st[i] = true;
            path[pos+1] = i;
            dfs(pos+1,i+1,tar);
            st[i] = false;
        }
    }
}
int main()
{
    cout << endl;
    cin >> n;
    for(int i = 1; i <= n; i ++ )
    {
        dfs(0,1,i);
    }
    return 0;
}