Kirigaya Kazuto 2017-07-21 22:05:18 +08:00 committed by GitHub
parent 23dfdac7bb
commit eeb0729071
1 changed files with 47 additions and 0 deletions

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HDOJ/5729_dpppbr.cpp Normal file
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//不初始化你给我死全家
#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
#include<cstdlib>
using namespace std;
#define MS(x,y) memset(x,y,sizeof(x))
#define MP(x,y) make_pair(x,y)
#define lowbit(x) (x&(-x))
typedef long long LL;
inline void fre1(){freopen("input.txt","r",stdin);/*freopen("output.txt","w",stdout);*/}
inline void fre2(){fclose(stdin);/*fclose(stdout);*/}
const int MAXN=30+5;
const double EPS=1e-8;
const int MOD=1e9+7;
LL fact[MAXN*MAXN],C[MAXN][MAXN],dp[MAXN][MAXN];
int main()
{
int n=11;
fact[0]=1;
for(int i=1;i<=n*n;++i) fact[i]=fact[i-1]*3%MOD;
C[0][0]=1;
for(int i=1;i<MAXN;++i){
C[i][0]=C[i][i]=1;
for(int j=1;j<i;++j)
C[i][j]=(C[i-1][j]+C[i-1][j-1])%MOD;
}
for(int i=1;i<=10;++i){
for(int j=0;j<=10;++j){
dp[i][j]=fact[i*j];
if(i==1&&j==0) dp[i][j]=1;
for(int ii=1;ii<=i;++ii){
for(int jj=0;jj<=j;++jj){
if(i==ii&&j==jj) continue;
dp[i][j]-=C[i-1][ii-1]*C[j][jj]%MOD*dp[ii][jj]%MOD*fact[(i-ii)*(j-jj)]%MOD;
dp[i][j]=(dp[i][j]%MOD+MOD)%MOD;
}
}
}
}
int m;
while(~scanf("%d%d",&n,&m)) printf("%I64d\n",dp[n][m]);
return 0;
}