package com.alibaba;

public class MaxSubarray
{
	public static void main(String[] args)
	{
		int[] array = { 1, -2, -3, 4, 5, 6, -3, 4, -11 };

		int[] result = MaxSubarray.findMaxSubarray(array, 0, array.length - 1);

		for (int i = 0; i < result.length; i++)
		{
			System.out.println(result[i]);
			
		}

	}

	public static int[] findMaxCrossingSubarray(int[] array, int low, int mid, int high)
	{

		int leftsum = Integer.MIN_VALUE;
		int sum1 = 0;
		int maxleft = 0;

		for (int i = mid; i >= 0; i--)
		{
			sum1 = sum1 + array[i];

			if (sum1 > leftsum)
			{
				leftsum = sum1;
				maxleft = i;
			}
		}

		int rightsum = Integer.MIN_VALUE;
		int sum2 = 0;
		int maxright = 0;

		for (int j = mid + 1; j <= high; j++)
		{
			sum2 = +array[j];

			if (sum2 > rightsum)
			{
				rightsum = sum2;
				maxright = j;
			}
		}
		int[] result = new int[3];

		result[0] = maxleft;
		result[1] = maxright;
		result[2] = leftsum + rightsum;

		return result;
	}

	public static int[] findMaxSubarray(int[] array, int low, int high)
	{
		if (high == low)
		{
			int[] result = { low, high, array[low] };
			return result;
		} else
		{
			int mid = (int) Math.floor((low + high) / 2);
			int[] left = new int[3];
			int[] right = new int[3];
			int[] cross = new int[3];

			left = findMaxSubarray(array, low, mid);
			right = findMaxSubarray(array, mid + 1, high);
			cross = findMaxCrossingSubarray(array, low, mid, high);

			if (left[2] >= right[2] && left[2] >= cross[2])
				return left;
			else if (right[2] >= left[2] && right[2] >= cross[2])
				return right;
			else
				return cross;
		}

	}

}