int FindMaxSubArray(const vector<int>& v, int left, int right,int* i,int* j)
{
if (left > right)
return 0;
if (left == right)
{
*i = *j = left;
return v[left];
}
int MaxLeft1, MaxRight1,MaxLeft2, MaxRight2,MaxLeft3, MaxRight3;
int mid = left + (right - left) / 2;
int LeftSum = FindMaxSubArray(v, left, mid, &MaxLeft1, &MaxRight1);
int RightSum = FindMaxSubArray(v, mid + 1, right, &MaxLeft2, &MaxRight2);
int MidSum = FindMidMaxSum(v, left, mid, right, &MaxLeft3, &MaxRight3);
if (LeftSum >= RightSum && LeftSum >= MidSum)
{
*i = MaxLeft1;
*j = MaxRight1;
return LeftSum;
}
else if (RightSum >= LeftSum && RightSum >= MidSum)
{
*i = MaxLeft2;
*j = MaxRight2;
return RightSum;
}
else
{
*i = MaxLeft3;
*j = MaxRight3;
return MidSum;
}
}
int FindMaxSubArray(int* nums, int low, int high)
{
int lsum,rsum,csum;
int mid;
if (low == high) {
//
// Base case. Only 1 element.
//
return nums[low];
} else {
mid = (low+high)/2;
lsum = FindMaxSubArray(nums,low,mid);
rsum = FindMaxSubArray(nums,mid+1,high);
csum = FindCrossMax(nums,low,mid,high);
}
if (lsum > rsum && lsum > csum) {
return lsum;
} else if (rsum > lsum && rsum > csum) {
return rsum;
}
return csum;
}
int main(int argc, char const *argv[]) {
std::vector<int> v;
v.push_back(1);v.push_back(1);v.push_back(1);v.push_back(5);v.push_back(1);v.push_back(-1);v.push_back(1); v.push_back(-5);
MaxSubArray result = FindMaxSubArray( v , 0 , v.size());
std::cout<< result.low << " " << result.high << " " << result.sum <<std::endl;
return 0;
}
int calculateMax(vector<int> prices)
{
int i;
vector<int> v;
int left, right;
for (i = 1;i < prices.size();++i)
{
v.push_back(prices[i] - prices[i - 1]);
cout << prices[i] - prices[i - 1]<<" ";
}
cout << endl;
int sum1=FindMaxSubArray(v, 0, v.size() - 1, &left, &right);
int a = left;
int b = right;
int sum2 = FindMaxSubArray(v, 0, left - 1, &left, &right);
left = a;
right = b;
int sum3 = FindMaxSubArray(v, right, v.size()-1, &left, &right);
if (sum1 <= sum2 && sum1 <= sum3)
{
if (sum2 < 0)
return sum3;
if (sum3 < 0)
return sum2;
return sum2 + sum3;
}
else if (sum2 <= sum1 && sum2 <= sum3)
{
if (sum1 < 0)
return sum3;
if (sum3 < 0)
return sum1;
return sum1 + sum3;
}
else
{
if (sum1 < 0)
return sum2;
if (sum2 < 0)
return sum1;
return sum1 + sum2;
}
}
void MaxSubArrayFinder::Find1(std::vector<int>& v, int& start, int& end, int& max_sum)
{
start = 0;
end = 0;
max_sum = 0;
if (v.size() > 0)
{
FindMaxSubArray(v, 0, v.size() - 1, start, end, max_sum);
}
}
void MaxSubArrayFinder::FindMaxSubArray(std::vector<int>& v, int low, int high, int& start, int& end, int& max_sum)
{
if (low == high)
{
start = low;
end = high;
max_sum = v[low];
return;
}
int mid = (low + high) / 2;
int left_start, left_end, left_max_sum;
FindMaxSubArray(v, low, mid, left_start, left_end, left_max_sum);
int right_start, right_end, right_max_sum;
FindMaxSubArray(v, mid + 1, high, right_start, right_end, right_max_sum);
int cross_start, cross_end, cross_max_sum;
FindMaxCrossingSubArray(v, low, mid, high, cross_start, cross_end, cross_max_sum);
if (left_max_sum >= right_max_sum && left_max_sum >= cross_max_sum)
{
start = left_start;
end = left_end;
max_sum = left_max_sum;
}
else if (right_max_sum >= left_max_sum && right_max_sum >= cross_max_sum)
{
start = right_start;
end = right_end;
max_sum = right_max_sum;
}
else
{
start = cross_start;
end = cross_end;
max_sum = cross_max_sum;
}
}
MaxSubArray FindMaxSubArray(std::vector<int> A, int l , int h ){
MaxSubArray ret;
int m;
if( h <= l ){
//std::cout << "if" << std::endl;
ret.low = l; ret.high = h; ret.sum = A[ l ]; ret.profit = A[ 0 ] - A[ h ];
return ret;
}else{
//std::cout << "else" << std::endl;
m = ( l + h ) / 2;
MaxSubArray la = FindMaxSubArray( A , l , m);
MaxSubArray ra = FindMaxSubArray( A , m + 1 , h );
//std::cout << "llega" << std::endl;
MaxSubArray ca = FindMaxCrossSubArray( A, l , m , h );
//std::cout << "else -- if" << std::endl;
if( la.sum >= ra.sum ){
return la;
}else if( ra.sum >= la.sum && ra.sum >= ca.sum ){
return ra;
}else{
return ca;
}
}
}
int maxSubArray(int* nums, int numsSize) {
return FindMaxSubArray(nums,0,numsSize-1);
}
