最大K乘积问题

#include "iostream"#include "string"#include "fstream"#include "algorithm"using namespace std;/*I(s,t)表示从s位开始的t位数字组成的十进制数f(i,j)表示I(0,i)的最大j乘积f(i,j) = max{ f(b,j-1) * I(b,i-b) }  1<=b<i */const int MAX = 9;int f[MAX][MAX];string num;int I(int i, int j){    string str = num.substr(i, i+j);  //截取    return atoi(string(str).c_str()); //转为数字}//返回n位十进制整数num的最大k乘积int dyna(int n, int k){    int i, j, b, temp;    int len = num.length();    for(i=1; i<=len; i++)        f[i][1] = I(0, i);    for(i=2; i<=len; i++)        for(j=2; j<=k; j++)        {            f[i][j] = f[1][j-1] * I(1, i-1);            for(b=2; b<i; b++)            {                temp = f[b][j-1] * I(b, i-b);                if(temp > f[i][j])                    f[i][j] = temp;            }        }    return f[len][k];}int main(){    ifstream fin("k.txt");    int n, k;    cout << "输入十进制位数n=：";    fin >> n; cout << n;    cout << "\n输入划分的段数k=：";    fin >> k; cout << k;    cout << "\n输入十进制整数num=：";    fin >> num; cout << num << endl;    cout << num << "的最大" << k << "乘积为：" << dyna(n, k) << endl;    fin.close();    return 0;}