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

#include<cstdio>
#include<iostream>
#include<cmath>
#include<algorithm>
#include<cstring>
#include<cstdlib>
#include<queue>
#include<vector>
#include<map>
#include<stack>
#include<string>

using namespace std;

const long long MOD=123456781;

long long n,k;
long long C[1001][1001];
long long dp[1001][31];

long long dfs(long long x,long long y){
    if (dp[x][y]!=-1) return dp[x][y];
    if (x==0 && y==0) return 1;
    if (x!=0 && y==0) return 0;
    dp[x][y]=0;
    for (long long i=1;i<=x-y+1;i++){
            dp[x][y]=(dp[x][y]+dfs(x-i,y-1)*C[x][i]%MOD)%MOD;
    }
    return dp[x][y];
}

int main(){
    memset(dp,-1,sizeof(dp));
    memset(C,0,sizeof(C));
    for (long long i=0;i<=1000;i++) C[i][0]=1;
    for (long long i=1;i<=1000;i++){
            for (long long j=1;j<=1000;j++){
                    C[i][j]=(C[i-1][j]+C[i-1][j-1])%MOD;
            }
    }
    while (scanf("%lld%lld",&n,&k)==2){
            printf("%lld
",dfs(n,k));
    }
    return 0;
}
/*
1 1
2 2
*/