求数组子数组之和最大值

求数组子数组之和最大值（way1）
int Max_sum(int *arr, size_t size)
{
    int max_sum = 0;
    for (int i = 0; i < size; i++)
    {
        int sum = 0;
        for (int j = i; j < size; j++)
        {
            sum += arr[j];
            if (sum>max_sum)
            {
                max_sum = sum;
            }
        }
    }
    return max_sum;
}
//（way2）
int _max(int x, int y)
{
    return( x > y )? x : y;
}
int Max_sum(int *arr, int size)
{
    int Start = arr[size - 1];
    int All = arr[size - 1];
    for (int i = size- 2; i >= 0; i--)
    {
        Start = _max(arr[i], Start + arr[i]);
        All = _max(Start, All);
    }
    return All;
}
int main()
{
    int arry[] = {2,-5,2,9,-10,4,5,8,-8};
    cout << Max_sum(arry, sizeof(arry) / sizeof(arry[0])) << endl;
    //  18
    system("pause");
    return 0;
}