You are given an array that may contain both positive and negative integers. You want to find the sum of the contiguous subarray of numbers which has the maximum sum using Divide and Conquer approach.

For example, if the given array is $[-1,5,6,-2,4,-7,6,-4],$ then the maximum subarray sum is $13.$ The subarray is $[5,6,-2,4]$

Show the simulation of finding the maximum sum subarray.

Write the pseudocode for finding the cross sum.