P1088 [NOIP2004 普及组] 火星人

#include <bits/stdc++.h>
using namespace std;
const int maxn = 10005;
int n,m;
int vis[maxn];
int mars[maxn];
int ans[maxn];
int num = 0;
bool return0 = false;//直接结束
void dfs(int x)
{
   if (return0)//直接结束
   {
      return;
   }
   if (x > n)
   {
      num++;
      if (num == m + 1)
      {
         return0 = true;//直接结束
         for (int i = 1; i <= n; i++)
         {
            cout << ans[i] << " ";
         }
      }
   }
   for (int i = 1; i <= n; i++)
   {
      if (num == 0)
      {
         i = mars[x];//每个i只排列>mars[i]的数字
      }
      if (vis[i] == 0)
      {
         vis[i] = 1;
         ans[x] = i;
         dfs(x + 1);//位置向后移动
         vis[i] = 0;
      }
   }
}
int main() // 组合问题
{
   cin >> n >> m;
   for (int i = 1; i <= n; i++)
   {
      cin >> mars[i];
   }
   dfs(1);
}