Hang electric brush oj title (2062)

Subset sequence (unintelligible)

Subject description:

Consider the aggregate An= { 1, 2, …, n }. For example, A1={1}, A3={1,2,3}. A subset sequence is defined as a array of a non-empty subset. Sort all the subset sequece of An in lexicography order. Your task is to find the m-th one.

Input

The input contains several test cases. Each test case consists of two numbers n and m ( 0< n<= 20, 0< m<= the total number of the subset sequence of An ).

Output

For each test case, you should output the m-th subset sequence of An in one line.

Sample Input

1 1 
2 1 
2 2 
2 3 
2 4 
3 10

Sample Output

1 
1 
1 2 
2 
2 1 
2 3 1

By the answer:

#include<stdio.h>
int main()
{
    int n,i,group;
    int s[21];        //每组首字母 
    __int64 m; 
    __int64 c[21]={0};     //每组个数 
   
    for(i=1;i<21;i++){
   	    c[i]=(i-1)*c[i-1]+1;
    }
	while(scanf("%d%I64d",&n,&m)!=EOF){
		for(i=0;i<21;i++){        //初始化首元素 
			s[i]=i;
		}
		while(n--&&m){
			if (group= m / c[n+1] + ((m % c[n+1]) ? 1 : 0))    //计算组数 
            {
                printf("%d", s[group]);
                for (i = (int)group; i <= n; s[i]=s[i+1], i++);     //删除首元素 
                m -= (group- 1) * c[i] + 1;            //计算在第几个 
                if(m==0){
				    printf("\n");	
				}else{
					printf(" "); 
				}
            }
		}
	} 
   
    return 0;
}