乘积最大

#include<iostream>
#include<cstring>
#include<cstdio>
#include<algorithm>
#define inf 0x7fffffff
using namespace std;
int n,k;
long long dp[105][15];
char shuzi[50];
long long sigma(int l,int r)
{
    long long res = 0;
    for (int i = l; i < r; ++i) {
        res = res * 10 + shuzi[i] -‘0‘ ;
    }
    return res;
}
int dfs(int i,int j)
{
    if(dp[i][j]!=-1)return dp[i][j];
    if (j == 0) return sigma(i,n);
    for (int p = i; p < n; p++)
        dp[i][j] = max (dp[i][j], sigma(i,p)*dfs(p,j-1));
    return dp[i][j];
}
int main()
{
    scanf("%d%d",&n,&k);
    scanf("%s",shuzi);
    memset(dp,-1,sizeof(dp));
    cout<<dfs(0,k);
    puts("");
    return 0;
}

#include<iostream>
#include<cstring>
#include<cstdio>
#include<algorithm>
#define inf 0x7fffffff
using namespace std;
int n,k;
int dp[41][41][6];
char shuzi[50];
inline int _max(int a,int b,int c)
{
    return max(max(a,b),c);
}
long long sigma(int l,int r)
{
    long long res = 0;
    for (int i = l; i <= r; ++i) {
        res = res * 10 + shuzi[i] -‘0‘ ;
    }
    return res;
}
int dfs(int i,int j,int k)
{
    if (k<0)    return 0;
    if (dp[i][j][k]!=0) return dp[i][j][k];
    if (k==0)    {
        dp[i][j][0]=sigma(i,j);
        return dp[i][j][0];
    }
    for (int p = i; p < j; p++)
            dp[i][j][k] = _max (dfs(i,p,k-1)*sigma(p+1,j), sigma(i,p)*dfs(p+1,j,k-1),dp[i][j][k]);
    return dp[i][j][k];
}
int main()
{
    scanf("%d%d",&n,&k);
    scanf("%s",shuzi+1);
    cout<<dfs(1,n,k);
    puts("");
    return 0;
}