我的可以AC

#include<bits/stdc++.h>
using namespace std;
int main(){
	freopen("da.in","r",stdin);
	freopen("da.out","w",stdout);
	ios::sync_with_stdio(false);
    cin.tie(0);
	long long n,m,sum[10005]={},ans=0;
	cin>>n>>m;
	long long a[25];
	for(int j=1;j<=n;j++){
		cin>>a[j];
	}
	for(int i=1;i<=m;i++){
		sum[i]=0;
		for(int j=1;j<=n;j++){
			if(i%a[j]==0){
				sum[i]++;
			}
		}
		ans=max(ans,sum[i]);
	}
	cout<<ans;
	return 0;
}

其实看看数据范围，就是个暴力枚举。

#include <bits/stdc++.h>
using namespace std;
int n, m;
int a[25];
int main()
{
    freopen("da.in", "r", stdin);
    freopen("da.out", "w", stdout);
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
        cin >> a[i];
    int ans = 0;
    for (int i = 1; i <= m; i++)
    {
        int now = 0;
        for (int j = 1; j <= n; j++)
            if (i % a[j] == 0)
                now++;
        ans = max(ans, now);
    }
    cout << ans;
    return 0;
}