E. The Values You Can Make 背包，同时DP

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <assert.h>
#define IOS ios::sync_with_stdio(false)
using namespace std;
#define inf (0x3f3f3f3f)
typedef long long int LL;


#include <iostream>
#include <sstream>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <string>
#include <bitset>
const int maxn = 500 + 20;
bool dp[maxn][maxn];
set<int>ans;
void work() {
    int n, k;
    cin >> n >> k;
    dp[0][0] = true;
    for (int i = 1; i <= n; ++i) {
        int x;
        cin >> x;
        for (int j = k; j >= 0; --j) {
            for (int h = j; h >= 0; --h) {
                if (j >= x) { //第一个集合
                    dp[j][h] = dp[j][h] || dp[j - x][h];
                }
//                if (h >= x) {
//                    dp[j][h] = dp[j][h] || dp[j][h - x];
//                }
                if (h >= x && j >= x) {
                    dp[j][h] = dp[j][h] || dp[j - x][h - x];
                }

            }
        }
    }
//    cout << dp[5][0] << endl;
    for (int i = 0; i <= k; ++i) {
        if (dp[k][i] == false) continue;
        ans.insert(i);
    }
    cout << ans.size() << endl;
    for (set<int> :: iterator it = ans.begin(); it != ans.end(); ++it) {
        cout << *it << " ";
    }
}

int main() {
#ifdef local
    freopen("data.txt", "r", stdin);
//    freopen("data.txt", "w", stdout);
#endif
    work();
    return 0;
}