最大子序列和（包括路徑記錄）

#include
#include <stack>
using namespace std;

#define MAX 999
#define BIG 101


int a[BIG];

void max_sum(int a[],int n)
{
int maxsum = 0;
int nowsum = 0;
///////////////
int nowhead=0;
int maxhead = 0;
////////////////
int tail = 0;
int flag = 1;
for (int i = 0; i < n; i++)
{


nowsum += a[i];
if (a[i] > 0 && flag == 1) //即首位或負數後一位 就設置爲可能起點
{
flag = 2;           //其餘正數位，不參與
nowhead = i;
}


if (nowsum > maxsum)
{
maxsum = nowsum;
maxhead = nowhead;
tail = i;
}


else if (nowsum < 0) //若當前子序列之和小於0 則置零
{
nowsum = 0;
flag = 1;  //喚醒
}
}


if (maxsum == 0) cout << "不存在最大子序列" << endl;
else 
{
cout <<"最大子序列和爲："<< maxsum << endl;
if (maxhead == tail) cout <<"最大子序列只有一位："<< maxhead+1 << endl;
else
{
cout << "最大子序列路徑爲：" << maxhead + 1 << "->" << tail + 1 << endl;
}
}
}


int main()
{
int n;
while (cout << "輸入個數：",cin>>n)
{
memset(a, 0, sizeof(a));
cout << "輸入數值：";
for (int i = 0; i < n; i++) cin >> a[i];
max_sum(a, n);
getchar();
getchar();
    }
return 0;
}