input: Write a function to find the maximum element in an array using divide and conquer approach.
  assert findMaxElement([1, 3, 5, 7, 9], 0, 4) == 9
  assert findMaxElement([2, 20, 8, 4, 6], 0, 4) == 20
  assert findMaxElement([-1, -3, -5, -7, -9], 0, 4) == -1
output: def findMaxElement(arr, low, high):
      if low == high:
          return arr[low]
      
      mid = (low + high) // 2
      
      max1 = findMaxElement(arr, low, mid)
      max2 = findMaxElement(arr, mid + 1, high)
      
      return max(max1, max2)