static int maxSubSum(const int a[], int left, int right)
{
int maxLeftSum, maxRightSum;
int maxLeftBorderSum, maxRightBorderSum;
int leftBorderSum, rightBorderSum;
int center, i;
if (left == right) /* Base Case*/
if (a[left] > 0)
return a[left];
else
return 0;
center = (left + right) / 2;
maxLeftSum = maxSubSum(a, left, center);
maxRightSum = maxSubSum(a, center+1, right);
maxLeftBorderSum = 0;
leftBorderSum = 0;
for (i = center; i >= left; --i) {
leftBorderSum += a[i];
if (leftBorderSum > maxLeftBorderSum)
maxLeftBorderSum = leftBorderSum;
}
maxRightBorderSum = 0;
rightBorderSum = 0;
for (i = center+1; i <= right; ++i) {
rightBorderSum += a[i];
if (rightBorderSum > maxRightBorderSum)
maxRightBorderSum = rightBorderSum;
}
return max3(maxLeftSum, maxRightSum, maxLeftBorderSum+maxRightBorderSum);
}
int maxSubSum(const int *src,int left,int right){
int maxLeftSum, maxRightSum;
int maxLeftBorderSum = 0, maxRightBorderSum = 0;
int leftBorderSum = 0, rightBorderSum = 0;
int center, i;
if(left == right){
return *(src + left) ;
}
center = (right + left)/2;
maxLeftSum = maxSubSum(src, left ,center);
maxRightSum = maxSubSum(src, center + 1,right);
maxLeftBorderSum = *(src + center);
for (i = center; i >= left; --i)
{
if((leftBorderSum += *(src + i)) > maxLeftBorderSum)
maxLeftBorderSum = leftBorderSum;
}
maxRightBorderSum = *(src + center + 1);
for (i = center + 1; i <= right; ++i)
{
if((rightBorderSum += *(src + i)) > maxRightBorderSum)
maxRightBorderSum = rightBorderSum;
}
return MAX((maxLeftBorderSum + maxRightBorderSum), MAX(maxLeftSum, maxRightSum));
}
int main()
{
const int a[] = {4, -3, 5, -2, -1, 2, 6, -2};
printf("max sub sum: %d\n", maxSubSum(a, 0, 7));
return 0;
}
int main()
{
int *a;
int i,len;
printf("请输入数组长度：\n");
scanf("%d",&len);
a = (int *)malloc(len * sizeof(int));
printf("请输入数组元素：\n");
for(i = 0;i < len;i++)
{
scanf("%d",a+i);
}
maxSubSum(a,len);
free(a);
return 0;
}
int main() {
std::array<int, 7> a {{-10, -1 , -5, 14, -3, 4, -7}};
std::cout << maxSubSum(a) << std::endl;
return 0;
}
//最大子序列的和，时间--O(N*logN)，空间--0
int maxSubsequenceSum(const int *src, int len){
return maxSubSum(src, 0, len - 1);
}
