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题目链接:
http://acm.hdu.edu.cn/showproblem.php?pid=2512
#include <cmath>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int maxn = 2000;
const int mod = 1000;
#define met(a,b) memset(a,b,sizeof(a))
int bell[maxn+10],stirling[maxn+10][maxn+10];
void num()
{
met(bell,0);
for(int i=1;i<=maxn;i++)
{
stirling[i][0]=0;
stirling[i][i]=1;
}
stirling[0][0]=1;
for(int i=1;i<=maxn;i++)
for(int j=1;j<i;j++)
stirling[i][j]=(stirling[i-1][j]*j+stirling[i-1][j-1])%mod;
for(int i=1;i<=maxn;i++)
for(int j=1;j<=i;j++)
bell[i]=(bell[i]+stirling[i][j])%mod;
}
int main()
{
num();
int t;
scanf("%d",&t);
while(t--)
{
int n;
scanf("%d",&n);
printf("%d\n",bell[n]);
}
}
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原文地址:http://www.cnblogs.com/TAT1122/p/5866010.html