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Add Deck of Cards solution

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Donne Martin 2017-03-03 18:51:00 -08:00
parent 98819e2a06
commit 0f517c709e
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solutions/object_oriented_design/deck_of_cards/__init__.py Normal file
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solutions/object_oriented_design/deck_of_cards/deck_of_cards.ipynb Normal file
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{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/system-design-primer-primer)."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Design a deck of cards"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Constraints and assumptions\n",
"\n",
"* Is this a generic deck of cards for games like poker and black jack?\n",
" * Yes, design a generic deck then extend it to black jack\n",
"* Can we assume the deck has 52 cards (2-10, Jack, Queen, King, Ace) and 4 suits?\n",
" * Yes\n",
"* Can we assume inputs are valid or do we have to validate them?\n",
" * Assume they're valid"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Solution"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Overwriting deck_of_cards.py\n"
]
}
],
"source": [
"%%writefile deck_of_cards.py\n",
"from abc import ABCMeta, abstractmethod\n",
"from enum import Enum\n",
"import sys\n",
"\n",
"\n",
"class Suit(Enum):\n",
"\n",
" HEART = 0\n",
" DIAMOND = 1\n",
" CLUBS = 2\n",
" SPADE = 3\n",
"\n",
"\n",
"class Card(metaclass=ABCMeta):\n",
"\n",
" def __init__(self, value, suit):\n",
" self.value = value\n",
" self.suit = suit\n",
" self.is_available = True\n",
"\n",
" @property\n",
" @abstractmethod\n",
" def value(self):\n",
" pass\n",
"\n",
" @value.setter\n",
" @abstractmethod\n",
" def value(self, other):\n",
" pass\n",
"\n",
"\n",
"class BlackJackCard(Card):\n",
"\n",
" def __init__(self, value, suit):\n",
" super(BlackJackCard, self).__init__(value, suit)\n",
"\n",
" def is_ace(self):\n",
" return True if self._value == 1 else False\n",
"\n",
" def is_face_card(self):\n",
" \"\"\"Jack = 11, Queen = 12, King = 13\"\"\"\n",
" return True if 10 < self._value <= 13 else False\n",
"\n",
" @property\n",
" def value(self):\n",
" if self.is_ace() == 1:\n",
" return 1\n",
" elif self.is_face_card():\n",
" return 10\n",
" else:\n",
" return self._value\n",
"\n",
" @value.setter\n",
" def value(self, new_value):\n",
" if 1 <= new_value <= 13:\n",
" self._value = new_value\n",
" else:\n",
" raise ValueError('Invalid card value: {}'.format(new_value))\n",
"\n",
"\n",
"class Hand(object):\n",
"\n",
" def __init__(self, cards):\n",
" self.cards = cards\n",
"\n",
" def add_card(self, card):\n",
" self.cards.append(card)\n",
"\n",
" def score(self):\n",
" total_value = 0\n",
" for card in card:\n",
" total_value += card.value\n",
" return total_value\n",
"\n",
"\n",
"class BlackJackHand(Hand):\n",
"\n",
" BLACKJACK = 21\n",
"\n",
" def __init__(self, cards):\n",
" super(BlackJackHand, self).__init__(cards)\n",
"\n",
" def score(self):\n",
" min_over = sys.MAXSIZE\n",
" max_under = -sys.MAXSIZE\n",
" for score in self.possible_scores():\n",
" if self.BLACKJACK < score < min_over:\n",
" min_over = score\n",
" elif max_under < score <= self.BLACKJACK:\n",
" max_under = score\n",
" return max_under if max_under != -sys.MAXSIZE else min_over\n",
"\n",
" def possible_scores(self):\n",
" \"\"\"Return a list of possible scores, taking Aces into account.\"\"\"\n",
" # ...\n",
"\n",
"\n",
"class Deck(object):\n",
"\n",
" def __init__(self, cards):\n",
" self.cards = cards\n",
" self.deal_index = 0\n",
"\n",
" def remaining_cards(self):\n",
" return len(self.cards) - deal_index\n",
"\n",
" def deal_card():\n",
" try:\n",
" card = self.cards[self.deal_index]\n",
" card.is_available = False\n",
" self.deal_index += 1\n",
" except IndexError:\n",
" return None\n",
" return card\n",
"\n",
" def shuffle(self): # ..."
]
}
],
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"display_name": "Python 3",
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"name": "python3"
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solutions/object_oriented_design/deck_of_cards/deck_of_cards.py Normal file
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from abc import ABCMeta, abstractmethod
from enum import Enum
import sys
class Suit(Enum):
HEART = 0
DIAMOND = 1
CLUBS = 2
SPADE = 3
class Card(metaclass=ABCMeta):
def __init__(self, value, suit):
self.value = value
self.suit = suit
self.is_available = True
@property
@abstractmethod
def value(self):
pass
@value.setter
@abstractmethod
def value(self, other):
pass
class BlackJackCard(Card):
def __init__(self, value, suit):
super(BlackJackCard, self).__init__(value, suit)
def is_ace(self):
return True if self._value == 1 else False
def is_face_card(self):
"""Jack = 11, Queen = 12, King = 13"""
return True if 10 < self._value <= 13 else False
@property
def value(self):
if self.is_ace() == 1:
return 1
elif self.is_face_card():
return 10
else:
return self._value
@value.setter
def value(self, new_value):
if 1 <= new_value <= 13:
self._value = new_value
else:
raise ValueError('Invalid card value: {}'.format(new_value))
class Hand(object):
def __init__(self, cards):
self.cards = cards
def add_card(self, card):
self.cards.append(card)
def score(self):
total_value = 0
for card in card:
total_value += card.value
return total_value
class BlackJackHand(Hand):
BLACKJACK = 21
def __init__(self, cards):
super(BlackJackHand, self).__init__(cards)
def score(self):
min_over = sys.MAXSIZE
max_under = -sys.MAXSIZE
for score in self.possible_scores():
if self.BLACKJACK < score < min_over:
min_over = score
elif max_under < score <= self.BLACKJACK:
max_under = score
return max_under if max_under != -sys.MAXSIZE else min_over
def possible_scores(self):
"""Return a list of possible scores, taking Aces into account."""
# ...
class Deck(object):
def __init__(self, cards):
self.cards = cards
self.deal_index = 0
def remaining_cards(self):
return len(self.cards) - deal_index
def deal_card():
try:
card = self.cards[self.deal_index]
card.is_available = False
self.deal_index += 1
except IndexError:
return None
return card
def shuffle(self): # ...