C :

#include <stdio.h>

int sum[51][51];
int a[51];
int N,M,g;
struct node
{
    int min,max;
}f[10][51];

int Init()
{
    int i;
    scanf("%d%d",&N,&M);
    for (i=1;i<=N;++i)
    {
        scanf("%d",&a[i]);
        a[i]=(a[i]+200000)%10;
    }
}
void Work()
{
    int k,i,j;
    for (i=1;i<=N;++i)
    {
        sum[i][i]=a[i];
        for (j=i;j<=N;++j) sum[i][j]=(sum[i][j-1]+a[j])%10;
        f[1][i].min=f[1][i].max=sum[1][i];
    }
    for (k=2;k<=M;++k)
        for (i=k;i<=N;++i)
        {
            f[k][i].min=g;
            f[k][i].max=0;
            for (j=k-1;j<i;++j)
            {
                if (f[k-1][j].min*sum[j+1][i]<f[k][i].min)
                    f[k][i].min=f[k-1][j].min*sum[j+1][i];
                if (f[k-1][j].max*sum[j+1][i]>f[k][i].max) 
                    f[k][i].max=f[k-1][j].max*sum[j+1][i];
            }
        }
    for (i=0;i<N;++i) a[i]=a[i+1];
    a[N]=a[0];
}
int main()
{
    int i,min,max;
    Init();
    g=(1<<31)-1;
    min=g;
    max=0;
    for (i=0;i<N;++i)
    {
        Work();
        if (min>f[M][N].min) min=f[M][N].min;
        if (max<f[M][N].max) max=f[M][N].max;
    }
    printf("%d\n%d",min,max);
    return 0;
}

C++ :

#include <stdio.h> 
#include <string.h>  
#define MAX 10000000  
#define MIN -10000000  
int line[200],n,m,Min,Max,sum[200];  
int f[200][20];  
int g[200][20]; 
int min(int a,int b)  
{  
    if(a>b)  
        return b;  
    return a;  
}  
int max(int a,int b)  
{  
    if(a>b)  
        return a;  
    return b;  
}  
void dp(int a[])  
{  
    int i,j,k;  
    for(i=1;i<=n;i++)  
        sum[i]=sum[i-1]+a[i];  
    for(i=0;i<=n;i++)  
        for(j=0;j<=m;j++)  
        {  
            f[i][j]=0;  
            g[i][j]=-1u>>1;  
        }  
		for(i=1;i<=n;i++)  
		{  
			f[i][1]=g[i][1]=(sum[i]%10+10)%10;  
		}  
		f[0][0]=1;  
		g[0][0]=1;  
		for(j=2;j<=m;j++)  
		{  
			for(i=j;i<=n;i++)  
			{  
				for(k=j-1;k<i;k++)  
				{  
					{  
						f[i][j]=max(f[i][j],f[k][j-1]*(((sum[i]-sum[k])%10+10)%10));  
						g[i][j]=min(g[i][j],g[k][j-1]*(((sum[i]-sum[k])%10+10)%10));  
					}  
				}  
			}  
		}  
		Max=max(Max,f[n][m]);  
		Min=min(Min,g[n][m]);  
}  
int main()  
{  
    int i,j,k;  
    Max=0;  
    Min=-1u>>1;  
    scanf("%d%d",&n,&m);  
    for(i=1;i<=n;i++)  
    {  
        scanf("%d",&line[i]);  
        line[i+n]=line[i];  
    }  
    for(i=0;i<n;i++)  
        dp(line+i);  
    printf("%d\n%d\n",Min,Max);  
    return 0;  
}  

Pascal :

var
    a,atmp:array[0..50] of longint;
    f:array[0..9,0..50] of longint;
    n,m,i:longint;
function g(a,b:longint):longint;
var
    i:longint;
begin
    g:=0;
    for i:=a to b do
        if atmp[i]>0 then g:=g+atmp[i]
        else g:=g+atmp[i];
    g:=(g+100000) mod 10;
end;
procedure question_min;
var
    t,i,j,k,tmp,min:longint;
begin
    min:=maxlongint;
    for t:=1 to n do
    begin
        for i:=1 to n do atmp[i]:=a[(i+t-1) mod n];
        atmp[n-t+1]:=a[n];f[0,1]:=atmp[1];
        for i:=1 to n do f[0,i]:=g(1,i);
        for i:=1 to m-1 do
            for j:=i+1 to n do
            begin
                f[i,j]:=maxlongint;
                for k:=i to j-1 do
                begin
                    tmp:=g(k+1,j);
                    if f[i,j]>tmp*f[i-1,k] then f[i,j]:=tmp*f[i-1,k];
                end;
            end;
        if f[m-1,n]<min then min:=f[m-1,n];
    end;
    writeln(min);
end;
procedure question_max;
var
    t,i,j,k,tmp,max:longint;
begin
    max:=0;
    for t:=1 to n do
    begin
        for i:=1 to n do atmp[i]:=a[(i+t-1) mod n];
        atmp[n-t+1]:=a[n];f[0,1]:=atmp[1];
        for i:=1 to n do f[0,i]:=g(1,i);
        for i:=1 to m-1 do
            for j:=i+1 to n do
            begin
                f[i,j]:=0;
                for k:=i to j-1 do
                begin
                    tmp:=g(k+1,j);
                    if f[i,j]<tmp*f[i-1,k] then f[i,j]:=tmp*f[i-1,k];
                end;
            end;
        if f[m-1,n]>max then max:=f[m-1,n];
    end;
    writeln(max);
end;
begin
    readln(n,m);
    for i:=1 to n do readln(a[i]);
    question_min;
    question_max;
end.