codecakes

# naive solution
class Solution:
    POS_NUM = 1000
    def removeDuplicates(self, nums: List[int]) -> int:
        start = 0
        n = len(nums)
        end = n - 1
        for start in iter(lambda: start, end):
            if start > end:
                break

codecakes

NATO_BAG = {
    'A': 'Alpha',
    'B': 'Bravo',
    'C': 'Charlie',
    'D': 'Delta',
    'E': 'Echo',
    'F': 'Foxtrot',
    'G': 'Golf',
    'H': 'Hotel',
    'I': 'India',

codecakes

# Definition for a binary tree node.
#
# defmodule TreeNode do
#   @type t :: %__MODULE__{
#           val: integer,
#           left: TreeNode.t() | nil,
#           right: TreeNode.t() | nil
#         }
#   defstruct val: 0, left: nil, right: nil
# end

codecakes

class Solution:
    def subsets(self, nums: List[int]) -> List[List[int]]:
        def do_generate(result, slate, subset):
            result += [slate]
            for idx, num in enumerate(subset):
                new_subset = subset[idx+1:]
                do_generate(result, slate + [num], new_subset)
            return result
        return do_generate([], [], nums)
    

codecakes

def find_combinations(n, k):
    """
    Args:
     n(int32)
     k(int32)
    Returns:
     list_list_int32
    """
    array = list(range(1,n+1))
    result = set()

codecakes

def fib(n):
    # print(f"for fib {n}")
    a, b = 0, 1
    if n == a: return a
    if n == b: return b
    return do_fib(n-1, b, a+b)


def do_fib(n, /, a=0, b=1):
    if n == 0: return a

codecakes

• Pattern match.
• Keep consistent level of abstraction per function.
• Don't mix pure functions with IO functions. Segregate.
• Build upon ubiquituous domain language.
• Define Interfaces for service layer around infrastructure and application.
• Partial function composition == Dependency Injection. But it is not a preferred functional pattern.
• Don't YAGNI
• If you find yourself passing parameters and adding conditional..the abstraction is incorrect.
• Build upon these foundational low-level architectural design patterns:
• Value objects, Business Domains, Service Layers

codecakes

HA principles: CAP done right

• Design in isolation (Partition)
  • 2 business modules must communicate over message pattern. They are not considered business modules if one requires the other, in which case they don’t need to communicate over messages if a business process has to die, all interconnected business modules must die
  • process are stateless
  • fault tolerant implies scalability implies concurrency and concurrent business processes
• Availability
  • its better to die on fault and restart, then drag and build up the pile of error
• when a process dies, fault detection and communicating fault is important

codecakes

defmodule ToHex do

  @hex_base 16

  def to_hex(0), do: 0

  def to_hex(num) when is_number(num) do
    div(num, @hex_base)
    |> IO.inspect
    |> then(& {to_hex(&1), rem(num, @hex_base)})

codecakes

x = [1,2,3]
if len(x) < 3:
  return x
else:
  return [4,5,6]