CDOJ 631 敢说敢做 记忆化搜索and动规
//跟沈爷学的 传送门http://www.cnblogs.com/Xiper/p/4639636.html
1 #include<cstdio> 2 #include<iostream> 3 #include<cmath> 4 #include<algorithm> 5 #include<cstring> 6 #include<cstdlib> 7 #include<queue> 8 #include<vector> 9 #include<map> 10 #include<stack> 11 #include<string> 12 13 using namespace std; 14 15 const long long MOD=123456781; 16 17 long long n,k; 18 long long C[1001][1001]; 19 long long dp[1001][31]; 20 21 long long dfs(long long x,long long y){ 22 if (dp[x][y]!=-1) return dp[x][y]; 23 if (x==0 && y==0) return 1; 24 if (x!=0 && y==0) return 0; 25 dp[x][y]=0; 26 for (long long i=1;i<=x-y+1;i++){ 27 dp[x][y]=(dp[x][y]+dfs(x-i,y-1)*C[x][i]%MOD)%MOD; 28 } 29 return dp[x][y]; 30 } 31 32 int main(){ 33 memset(dp,-1,sizeof(dp)); 34 memset(C,0,sizeof(C)); 35 for (long long i=0;i<=1000;i++) C[i][0]=1; 36 for (long long i=1;i<=1000;i++){ 37 for (long long j=1;j<=1000;j++){ 38 C[i][j]=(C[i-1][j]+C[i-1][j-1])%MOD; 39 } 40 } 41 while (scanf("%lld%lld",&n,&k)==2){ 42 printf("%lld\n",dfs(n,k)); 43 } 44 return 0; 45 } 46 /* 47 1 1 48 2 2 49 */
