hdu 1027 输出第m个全排列（next_permutation）

Sample Input
6 4 //输出第4个全排列
11 8

Sample Output
1 2 3 5 6 4
1 2 3 4 5 6 7 9 8 11 10

 # include <cstdio>
 # include <iostream>
 # include <algorithm>
 using namespace std ;

 int a[] ;

 int main ()
 {
     int n , m ;
     while (scanf("%d %d" , &n , &m) != EOF)
     {
         int i ;
         for (i =  ; i <= n ;i++)
            a[i] = i ;
         int num =  ;
         while (num < m)
         {
             next_permutation(a+ , a++n) ;
             num++ ;
         }
         for (i =  ; i <= n- ;i++)
           printf("%d " , a[i]) ;
         printf("%d\n",a[n]) ;
     }
 }