hdu 1331 Function Run Fun

http://acm.hdu.edu.cn/showproblem.php?pid=1331

 1 #include <cstdio>

 2 #include <cstring>

 3 #include <algorithm>

 4 using namespace std;

 5 

 6 int dp[30][30][30];

 7 

 8 int dfs(int a,int b,int c)

 9 {

10     if(a<=0||b<=0||c<=0) return 1;

11     if(dp[a][b][c]!=0) return dp[a][b][c];

12     if(a<b&&b<c)

13     {

14         return dp[a][b][c]=dfs(a,b,c-1)+dfs(a,b-1,c-1)-dfs(a,b-1,c);

15     }

16     else

17         return dp[a][b][c]=dfs(a-1,b,c)+dfs(a-1,b-1,c)+dfs(a-1,b,c-1)-dfs(a-1,b-1,c-1);

18 }

19 

20 int main()

21 {

22     int a,b,c;

23     while(scanf("%d%d%d",&a,&b,&c)!=EOF)

24     {

25         if(a==-1&&b==-1&&c==-1) break;

26         if(a<=0||b<=0||c<=0)

27         {

28             printf("w(%d, %d, %d) = %d\n",a,b,c,1);

29         }

30         else if(a>20||b>20||c>20)

31         {

32             printf("w(%d, %d, %d) = %d\n",a,b,c,dfs(20,20,20));

33         }

34         else

35             printf("w(%d, %d, %d) = %d\n",a,b,c,dfs(a,b,c));

36     }

37     return 0;

38 }

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