
```cpp
#include <bits/stdc++.h>
using namespace std;
const int N = 110;
const int INF = 0x3f3f3f3f;
int m, n, a[N], s[N], v[N][N];
int dpx[N][N][10], dpn[N][N][10];
int Mod10(int a)
{
	if(a >= 0)
		return a % 10;
	else
		return a % 10 + 10;
}
int main()
{
    cin >> n >> m;
    for(int i = 1; i <= n; ++i)
    {
    	cin >> a[i];
    	a[i+n] = a[i];
    }
    for(int i = 1; i < 2*n; ++i)
    	s[i] = s[i-1] + a[i];
	for(int l = 1; l <= n; ++l)
		for(int i = 1; i+l-1 < 2*n; ++i)
		{
			int j = i+l-1;
			v[i][j] = Mod10(s[j]-s[i-1]);
		}
	memset(dpn, 0x3f, sizeof(dpn));
	for(int l = 1; l <= n; ++l)
		for(int i = 1; i <= n; ++i)
		{
			int j = i+l-1;
			dpx[i][j][1] = dpn[i][j][1] = v[i][j];
			for(int k = 2; k <= m && k <= l; ++k)
				for(int h = i+k-1; h <= j; ++h) 
				{
					dpx[i][j][k] = max(dpx[i][j][k], dpx[i][h-1][k-1]*v[h][j]);
					dpn[i][j][k] = min(dpn[i][j][k], dpn[i][h-1][k-1]*v[h][j]);
				}
		}
	int mx = 0, mn = INF;
	for(int i = 1; i <= n; ++i)
	{
		int j = i+n-1;
		mx = max(mx, dpx[i][j][m]);
		mn = min(mn, dpn[i][j][m]);
	}
	cout << mn << endl << mx;
    return 0;
}
```
9ms + AC代码
