/*

Find the contiguous subarray within an array (containing at least one number) which has the largest sum.

For example, given the array [−2,1,−3,4,−1,2,1,−5,4],

the contiguous subarray [4,−1,2,1] has the largest sum = 6.

*/

#include <iostream>

using namespace std;

int maximumSubarray(int *a, int n, int& startIndex, int& endIndex)

{

if (n == 0)

{

return 0;

}

int globalMax(a[0]), localMax(a[0]), localStart(0), localEnd(0);

for (int i = 1; i < n; ++i)

{

localMax += a[i];

if (localMax < 0)

{

localMax = 0;

localStart = localEnd = i + 1;

}

else

{

localEnd = i;

if (localMax > globalMax)

{

startIndex = localStart;

endIndex = localEnd;

globalMax = localMax;

}

}

}

return globalMax;

}

int main(int argc, char ** argv)

{

int a[] = {-2,1,-3,4,-1,2,1,-5,4};

int startIndex(0), endIndex(0);

int maxSum = maximumSubarray(a, sizeof(a)/sizeof(int), startIndex, endIndex);

cout << "Maximum subarray sum is: " << maxSum << endl;

for (int i = startIndex; i <= endIndex; ++i)

{

cout << a[i] << ", " ;

}

cout << endl;

return 0;

}