斯特林数2
将n个两两不相同数划分到m个集合中,求方案数
图解
代码
import java.util.*;
public class Main{
static int MODE = 1000000007;
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
int n = sc.nextInt(), m = sc.nextInt();
long[][] f = new long[n+1][m+1];
f[0][0] = 1;
for(int i = 1; i <= n; i++){
for(int j = 1; j <= m; j++){
f[i][j] = (f[i-1][j-1] + (long)j*f[i-1][j])%MODE;
}
}
System.out.println(f[n][m]);
}
}