题目链接
1 /*
2 Name:
3 Copyright:
4 Author:
5 Date: 2018/5/2 11:07:16
6 Description:输出第m小的序列
7 */
8 #include <iostream>
9 #include <cstdio>
10 #include <vector>
11 #include <algorithm>
12 #include <cstring>
13 using namespace std;
14 int fac[] = {1,1,2,6,24,120,720,5040,40320};//阶乘
15 //康托展开的逆运算,{1...n}的全排列，中的第k个数为s[]
16 void reverse_kangtuo(int n,int k,int s[])
17 {
18 int i, j, t, vst[1001]={0};
19 --k;
20 for (i=0; i<n; i++)
21 {
22 if (n-i-1 > 8) {
23 t = k/fac[8];
24 } else {
25 t = k/fac[n-i-1];
26 }
27 for (j=1; j<=n; j++)
28 if (!vst[j])
29 {
30 if (t == 0) break;
31 --t;
32 }
33 s[i] = j;
34 vst[j] = 1;
35 if (n-i-1 > 8) {
36 k %= fac[8];
37 } else {
38 k %= fac[n-i-1];
39 }
40 }
41 }
42
43 int main()
44 {
45 int s[1005] ;
46 int m, n;
47 while (cin>>m>>n) {
48 memset(s, 0, sizeof(s)) ;
49 reverse_kangtuo(m, n, s);
50 cout<<s[0];
51 for (int i=1; i<m; i++) {
52 cout<<" "<<s[i];
53 }
54 cout<<endl;
55 }
56 return 0;
57 }
