C++ :

#include<iostream>

#include<string.h>

#include<algorithm>

using namespace std;
int  max(int a,long b )
{
 
  if(a>b)
	  return a;
  else
	  return b;
}

int main(){

    int n,K,a[45];

    char x;

    long dp[45][45];

    while(cin>>n>>K){

        memset(a,0,sizeof(a));

        memset(dp,0,sizeof(dp));

        for(int i=1;i<=n;i++){

            cin>>x;a[i]=x-'0';

        }

        for(int k=1;k<=K;k++){

                for(int i=k+1;i<=n;i++){

                    for(int j=k;j<i;j++){

                    int index1=1,num1=0,index2=j+1,num2=0;

                    while(index1<=j){

                            num1=num1*10+a[index1];index1++;

                    }

                    while(index2<=i){

                        num2=num2*10+a[index2];index2++;

                    }

                    if(k==1) dp[i][k]=max(dp[i][k],(long)num1*num2);

                    else dp[i][k]=max(dp[i][k],dp[j][k-1]*num2);

                }

            }

        }

        cout<<dp[n][K]<<endl;

    }

    return 0;

}

Pascal :

const MAXN=40;
MAXK=6;
var
i,j,l:longint;
n,K:longint;
s:string;
f:array[0..MAXN,0..MAXK] of int64;
a:array[0..MAXN,0..MAXN] of int64;
begin
{assign(input,'2000t2.in');reset(input);
assign(output,'2000t2.out');rewrite(output); }
readln(N,K);
readln(s);
fillchar(f,sizeof(f),0);
fillchar(a,sizeof(a),0);
for i:=1 to n do
begin
j:=ord(s[i]);
dec(j,ord('0'));
a[i,i]:=j;
end;
for i:=1 to n do
for j:=i+1 to n do a[i][j]:=a[i][j-1]*10+a[j][j];
for i:=1 to n do f[i][0]:=a[1][i];
for l:=1 to K do
for i:=l+1 to n do
begin
for j:=l-1+1 to i-1 do
if f[i][l]<f[j][l-1]*a[j+1][i] then f[i][l]:=f[j][l-1]*a[j+1][i];
end;
writeln(f[N][K]);
{close(input);
close(output);}
end.

Java :

import java.math.*;
import java.util.*;
public class Main { 
	public static void main(String[] args) {
		Scanner cin = new Scanner ( System.in );
		String str;
		int n ,k;
		while(cin.hasNext())
		{
		 n=cin.nextInt();
		 k=cin.nextInt();
		 str=cin.next();
		 BigInteger dp[][]=new BigInteger[41][7];
		 BigInteger num[][]=new BigInteger[41][41];
		 for(int i=1;i<=n;i++)
		 {
			 for(int j=i;j<=n;j++)
			 {
				 String s ="";
				 for(int l=i-1;l<j;l++)
				 {
					 s+=str.charAt(l);
				 }
				 BigInteger tmp = new BigInteger(s);
				 num[i][j] = tmp;
			 }
		 }
		 BigInteger t = new BigInteger("0");
		 for(int i=1;i<=n;i++)
		 {
			 for(int j=1;j<=k;j++)
			 {
				 dp[i][j]=t;
			 }
		 }
		 String s="";
		 for(int i=1;i<=n;i++)
		 {
			 s+=str.charAt(i-1);
			 BigInteger tmp = new BigInteger(s);
			 dp[i][0]=tmp;
		 }
		 for(int i=2;i<=n;i++)
		 {
			 for(int l=1;l<=k;l++)
			 {
				 for(int j=i-1;j>=1;j--)
				 {
					 dp[i][l]=dp[i][l].max(dp[j][l-1].multiply(num[j+1][i]));
				 }
			 }
		 }
		 System.out.println(dp[n][k]);
		}
		}
}