HDU - 1723 - Distribute Message

先上题目：

Distribute Message

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 1186    Accepted Submission(s): 547

Problem Description

The contest’s message distribution is a big thing in prepare. Assuming N students stand in a row, from the row-head start transmit message, each person can transmit message to behind M personals, and how many ways could row-tail get the message?

 

Input

Input may contain multiple test cases. Each case contains N and M in one line. (0<=M<N<=30)
When N=0 and M=0, terminates the input and this test case is not to be processed. 

 

Output

Output the ways of the Nth student get message.

 

Sample Input

4 1

4 2

0 0

 

Sample Output

1

3

Hint

4 1 : A->B->C->D

4 2 : A->B->C->D, A->C->D, A->B->D

　　

上代码：

#include <cstdio>
#include <cstring>
#define MAX 32
#define LL long long
using namespace std;

LL dp[MAX];

int main()
{
    int n,m;
    while(scanf("%d %d",&n,&m),(n+m)){
        memset(dp,0,sizeof(dp));
        dp[1]=1;
        for(int i=1;i<=n;i++){
            for(int j=1;j<=m && i+j<=n;j++){
                dp[i+j]+=dp[i];
            }
        }
        printf("%I64d\n",dp[n]);
    }
    return 0;
}