杭电 1027 Ignatius and the Princess II
Problem Description
Now our hero finds the door to the BEelzebub feng5166. He opens the door and finds feng5166 is about to kill our pretty Princess. But now the BEelzebub has to beat our hero first. feng5166 says, "I have three question for you, if you can work them out, I will release the Princess, or you will be my dinner, too." Ignatius says confidently, "OK, at last, I will save the Princess."
"Now I will show you the first problem." feng5166 says, "Given a sequence of number 1 to N, we define that 1,2,3...N-1,N is the smallest sequence among all the sequence which can be composed with number 1 to N(each number can be and should be use only once in this problem). So it's easy to see the second smallest sequence is 1,2,3...N,N-1. Now I will give you two numbers, N and M. You should tell me the Mth smallest sequence which is composed with number 1 to N. It's easy, isn't is? Hahahahaha......"
Can you help Ignatius to solve this problem?
"Now I will show you the first problem." feng5166 says, "Given a sequence of number 1 to N, we define that 1,2,3...N-1,N is the smallest sequence among all the sequence which can be composed with number 1 to N(each number can be and should be use only once in this problem). So it's easy to see the second smallest sequence is 1,2,3...N,N-1. Now I will give you two numbers, N and M. You should tell me the Mth smallest sequence which is composed with number 1 to N. It's easy, isn't is? Hahahahaha......"
Can you help Ignatius to solve this problem?
Input
The
input contains several test cases. Each test case consists of two
numbers, N and M(1<=N<=1000, 1<=M<=10000). You may assume
that there is always a sequence satisfied the BEelzebub's demand. The
input is terminated by the end of file.
Output
For
each test case, you only have to output the sequence satisfied the
BEelzebub's demand. When output a sequence, you should print a space
between two numbers, but do not output any spaces after the last number.
Sample Input
6 4
11 8
Sample Output
1 2 3 5 6 4
1 2 3 4 5 6 7 9 8 11 10
Author
Ignatius.L
一开始就知道stl库中有一个next_permutation()函数,但是不想用那个,想用递归写出来,但是失败啦!所以又回到了使用next_permutation()函数上!
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
1 #include <cstdio> 2 #include <algorithm> 3 using namespace std; 4 5 int main() 6 { 7 int p[1005], n, m, i; 8 while( scanf( "%d%d", &n, &m ) != EOF ) 9 { 10 memset( p, 0, 1005 * sizeof(int) ); 11 for( i = 0; i < n; i++ ) 12 p[i] = i+1; 13 m = m - 1; 14 while( m-- ) 15 next_permutation(p, p+n); 16 for( i = 0; i < n; i++ ) 17 { 18 printf( "%d", p[i] ); 19 if( i != (n-1) ) 20 printf( " " ); 21 else 22 printf( "\n" ); 23 } 24 25 } 26 return 0; 27 }