http://www.luogu.org/record/lists?pid=P1164

#include<cstdio>
#include<algorithm>
#include<cstring>
#define ms(i,j) memset(i,j, sizeof i);
using namespace std;
int n,m;
int a[105];
int f[10005];
int main()
{
    scanf("%d%d", &n, &m);
    for (int i=1;i<=n;i++) scanf("%d", &a[i]);
    ms(f,0); f[0] = 1;
    for (int i=1;i<=n;i++)
    for (int j=m;j>=a[i];j--)
    {
        f[j] += f[j-a[i]];
    }
    printf("%d\n", f[m]);
    return 0;
}