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 */

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