func_code: def quicksort(A, start, end):
      if end - start < 1:
          return
      i = j = start
      while i <= end:
          if A[i] <= A[end]:
              A[i], A[j] = A[j], A[i]
              j += 1
          i += 1
      quicksort(A, start, j - 2)
      quicksort(A, j, end)