dp水题

#include <iostream>
#include <cstring>
#include <cstdio>

using namespace std;

int dp[2010][2010];
int mod=1000000007;

int main()
{
    int T ;
    scanf("%d",&T);
    for(int t=1;t<=T;t++)
    {
        int a,b;
        char c;
        scanf("%d%c%d",&a,&c,&b);
        memset(dp,0,sizeof(dp));
        //dp[1][0]=1;
        dp[1][0]=1;
        for(int i=2;i<=a;i++)
        {
            int j;
            for(j=0;j<=b;j++)
            {
                if(i-1>j)
                {
                    dp[i][j]=(dp[i][j]+dp[i-1][j])%mod;
                }
                if(i>j-1)
                {
                    dp[i][j]=(dp[i][j]+dp[i][j-1])%mod;
                }
            }
        }
        cout<<"Case #"<<t<<": "<<dp[a][b]<<" ";
        memset(dp,0,sizeof(dp));
        dp[0][0]=1;
        for(int i=0;i<=a;i++)
        {
            int j;
            for(int j=1;j<=b;j++)
            {
                if(i<=j&&i>0)
                {
                    dp[i][j]=(dp[i-1][j]+dp[i][j])%mod;
                }
                if(i<=j-1)
                {
                    dp[i][j]=(dp[i][j]+dp[i][j-1])%mod;
                }
            }
        }
        cout<<dp[b][b]<<endl;
    }
    return 0;
}