求最大子数组，最大子乘积
#include <iostream>
#include <vector>
using namespace std;
int max(int a, int b, int c)
{
return (a > b) ? (a > c ? a : c) : (b > c ? b : c);
}
int min(int a, int b, int c)
{
return (a < b) ? (a < c ? a : c) : (b< c ? b: c);
}
int pro(vector<int> a)
{
if (a.size() == 0)
return 0;
if (a.size() == 1)
return a[0];
int p,q;
p= q = a[0];
int res = a[0];
int st1, ed1;
int st2, ed2;
st1= ed1 =st2=ed2= 0;
int res1 = a[0];
for (int i = 1;i < a.size();i++)
{
//p和q代表最大值和最小值
int temp1 = p;
int temp2 = q;
p = max(p*a[i], a[i], temp2*a[i]);//p和q代表当下以n为结尾的最大子数组的值
q = min(temp1*a[i], q*a[i], a[i]);
res = (res > p ? res : p);
res1 = (res1 < q ? res : q);
if (res == p)
{
if (p == a[i])
st1 = i;
if (p == temp2*a[i])
st1 = st2;
ed1 = i;
}
if (res1 == q)
{
if (q == a[i])
st2 = i;
if (q == temp1*a[i])
st2 = st1;
ed2 = i;
}
//res1 = (res1 < q ? res : q);
}
cout << st1 << ed1;
cout << endl << res1;
return res;
}
void main()
{
vector<int> M = { -1,2,3,4,9,-2,5,-3 };
cout << pro(M);
}
