OJ-Problems-Source/HDOJ/5209_autoAC.cpp
2016-09-13 04:52:40 +08:00

62 lines
1.2 KiB
C++

#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<iostream>
using namespace std;
const int mod=1000000007;
const int maxn=110005;
typedef long long LL;
LL jie[maxn],jie2[maxn];
int mm(int n,int m){
LL s=1,k=n;
while(m>0){
if(m&1){
s=s*k;
s%=mod;
}
k=k*k;
k%=mod;
m>>=1;
}
return s;
}
int zuhe(int n,int m){
LL s;
s=jie[n];
s=s*jie2[m];
s%=mod;
s=s*jie2[n-m];
s%=mod;
return s;
}
void init(void){
int i;
jie[0]=1;
jie2[0]=1;
for(i=1;i<=110000;i++){
jie[i]=jie[i-1]*i;
jie[i]%=mod;
jie2[i]=mm(jie[i],mod-2);
}
}
LL dp[1005];
int main()
{
int i,j,n,m,t,N=0;
cin>>t;
init();
while(t--){
cin>>n>>m;
memset(dp,0,sizeof(dp));
dp[0]=1;
for(i=1;i<=n;i++){
for(j=1;j<=i;j++){
dp[i]+=zuhe(i-1,j-1)*((dp[i-j]*zuhe(j+m-1,m-1))%mod);
dp[i]%=mod;
}
}
printf("Case #%d: %d\n",++N,dp[n]);
}
}