最大子数组的和以及最大子数组的乘积

dp[t] = func(arr[t],  operater(dp[t-1], arr[t]))

#include <iostream>
#include <cstring>
#include <cstdlib>
using namespace std;

float get_abs(const float &val)
{
return val > 0 ? val : -val;
}

template <typename T>
T get_min(const T &val1, const T &val2)
{
return val1 > val2 ? val2 : val1;
}

template <typename T>
T get_max(const T &val1, const T &val2)
{
return val1 > val2 ? val1 : val2;
}

float get_max_sub_mul(float arr[], int len)
{
int i = 0;
float last_max = 1.0;
float last_min = 1.0;
float maxp = 0.0;
float cur_max = 1.0;
float cur_min = 1.0;
for (i = 0; i < len; i++)
{
// last_max last_min 需要存储前面的值，因为需要用两次。
cur_max = get_max<float>(arr[i], get_max<float>(arr[i]*last_max, arr[i]*last_min));
cur_min = get_min<float>(arr[i], get_min<float>(arr[i]*last_max, arr[i]*last_min));
maxp = get_max<float>(maxp, cur_max);
last_max = cur_max;
last_min = cur_min;
}
return maxp;
}

int get_max_sum_arr(int arr[], int len)
{
int i = 0;
int maxp = 0;
int max_tmp = 0;
int start_ind = 0;
int end_ind = 0;
for (i = 0; i < len; i++)
{
if (max_tmp + arr[i] > arr[i]) {
max_tmp = max_tmp + arr[i];
} else {
max_tmp = arr[i];
start_ind = i;
}
if (max_tmp > maxp) {
maxp = max_tmp;
end_ind = i;
}
}
std::cout << "start_ind, end_ind: " << start_ind << ", " << end_ind << endl;
std::cout << "max sum: " << maxp << std::endl;
return maxp;
}

int main(int argc, char *argv[])
{
int arr[] = {1, -2, 3, 10, -4, 7, 2, -5};
int len = sizeof(arr) / sizeof(int);
std::cout << "array data" << std::endl;
int i = 0;
for (i = 0; i < len; i++)
{
std::cout << arr[i] << " ";
}
std::cout << std::endl;
std::cout << "max sub sum arr: " << get_max_sum_arr(arr, len) << std::endl;
std::cout << "--------------------------" << std::endl;
std::cout << "--------------------------" << std::endl;
//float arr_f[] = {1, -2, 3, 0.25, 10, -4, 0.35, 7, 2, -5};
float arr_f[] = {1, -2, 0, 3, 0.25, 10, -4, 0.35, 7, 2, -5};
len = sizeof(arr_f) / sizeof(float);
std::cout << "array data float: " << std::endl;
i = 0;
for (i = 0; i < len; i++)
{
std::cout << arr_f[i] << " ";
}
std::cout << std::endl;
std::cout << "max sub sum arr: " << get_max_sub_mul(arr_f, len) << std::endl;
return 0;
}