This notebook was prepared by Donne Martin. Source and license info is on GitHub.
* Prices: None or k: None -> None * Prices: [] or k <= 0 -> [] * Prices: [0, -1, -2, -3, -4, -5] * (max profit, list of transactions) * (0, []) * Prices: [2, 5, 7, 1, 4, 3, 1, 3] k: 3 * (max profit, list of transactions) * (10, [Type.SELL day: 7 price: 3, Type.BUY day: 6 price: 1, Type.SELL day: 4 price: 4, Type.BUY day: 3 price: 1, Type.SELL day: 2 price: 7, Type.BUY day: 0 price: 2])
Refer to the Solution Notebook. If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start.
from enum import Enum # Python 2 users: Run pip install enum34
class Type(Enum):
SELL = 0
BUY = 1
class Transaction(object):
def __init__(self, type, day, price):
self.type = type
self.day = day
self.price = price
def __eq__(self, other):
return self.type == other.type and \
self.day == other.day and \
self.price == other.price
def __repr__(self):
return str(self.type) + ' day: ' + \
str(self.day) + ' price: ' + \
str(self.price)
class StockTrader(object):
def find_max_profit(self, prices, k):
# TODO: Implement me
pass
The following unit test is expected to fail until you solve the challenge.
# %load test_max_profit.py
import unittest
class TestMaxProfit(unittest.TestCase):
def test_max_profit(self):
stock_trader = StockTrader()
self.assertRaises(TypeError, stock_trader.find_max_profit, None, None)
self.assertEqual(stock_trader.find_max_profit(prices=[], k=0), [])
prices = [5, 4, 3, 2, 1]
k = 3
self.assertEqual(stock_trader.find_max_profit(prices, k), (0, []))
prices = [2, 5, 7, 1, 4, 3, 1, 3]
profit, transactions = stock_trader.find_max_profit(prices, k)
self.assertEqual(profit, 10)
self.assertTrue(Transaction(Type.SELL,
day=7,
price=3) in transactions)
self.assertTrue(Transaction(Type.BUY,
day=6,
price=1) in transactions)
self.assertTrue(Transaction(Type.SELL,
day=4,
price=4) in transactions)
self.assertTrue(Transaction(Type.BUY,
day=3,
price=1) in transactions)
self.assertTrue(Transaction(Type.SELL,
day=2,
price=7) in transactions)
self.assertTrue(Transaction(Type.BUY,
day=0,
price=2) in transactions)
print('Success: test_max_profit')
def main():
test = TestMaxProfit()
test.test_max_profit()
if __name__ == '__main__':
main()
Review the Solution Notebook for a discussion on algorithms and code solutions.