1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
|
#include <stdio.h>
#include "util.h"
#ifdef __STDC__
double stirling(int n, int m)
#else
double stirling(n, m)
int n, m;
#endif
{
double **s, temp;
int i, j;
if(n < m)
return 0.0;
else if(n == m)
return 1.0;
else if(m == 0 && n > 0)
return 0.0;
else if(m == 1 && n > 0)
return 1.0;
s = (double **) mymalloc(m*sizeof(double *));
for(i=0; i<m; i++)
s[i] = (double *) mymalloc((n-m+1)*sizeof(double));
for(j=0; j<=n-m; j++)
s[0][j] = 1.0;
for(i=1; i<m; i++)
{
s[i][0] = 1.0;
for(j=1; j<=n-m; j++)
s[i][j] = (i+1)*s[i][j-1] + s[i-1][j];
}
temp = s[m-1][n-m];
for(i=0; i<m; i++)
free(s[i]);
return temp;
}
#if 0
main(int argc, char *argv[])
{
int n, m;
n = atoi(argv[1]);
m = atoi(argv[2]);
printf("S(%d,%d) = %f\n", n, m, stirling(n,m));
}
#endif
|
