Balance

http://poj.org/problem?id=1837

#include <stdio.h>
#include <string.h>
const int N=15002;
int dp[21][N];
int main()
{
    int n,num;
    int dis[21],w[21];
    memset(dp,0,sizeof(dp));
    scanf("%d%d",&n,&num);// n钩子数，num砝码数
    for (int i = 1; i <= n; i ++)
        scanf("%d",&dis[i]);
    for (int j = 1; j <= num; j ++)
        scanf("%d",&w[j]);
    dp[0][7500] = 1;//砝码数为0达到平衡的方法有一种
    for (int i = 1; i <= num; i ++)
    {
        for (int j = 0; j <= 15000; j ++)
        {
            if (dp[i-1][j])
            {
                for (int k  = 1; k <= n; k ++)
                {
                    //状态转移方程
                    dp[i][j+dis[k]*w[i]] += dp[i-1][j];
                }
            }
        }
    }
    printf("%d
",dp[num][7500]);
    return 0;
}