tvl-depot/deepmind/stock-price.py
William Carroll 5c9079a410 Splice ./universe directory into ./
Manually merging:
- README.md: I added the description from universe/README.md into the heading of
  dotfiles/README.md.
- .envrc: dotfiles/.envrc was a superset of universe/.envrc
- .gitignore: Adding some of the ignored patterns from universe/.gitignore to
  dotfiles/.gitignore

Everything else here should be a simple rename.
2020-01-29 14:43:20 +00:00

51 lines
1.3 KiB
Python

def get_max_profit(xs):
best_profit = xs[1] - xs[0]
lowest_buy = xs[0]
for x in xs[1:]:
best_profit = max(best_profit, x - lowest_buy)
lowest_buy = min(lowest_buy, x)
return best_profit
# Tests
import unittest
class Test(unittest.TestCase):
def test_price_goes_up_then_down(self):
actual = get_max_profit([1, 5, 3, 2])
expected = 4
self.assertEqual(actual, expected)
def test_price_goes_down_then_up(self):
actual = get_max_profit([7, 2, 8, 9])
expected = 7
self.assertEqual(actual, expected)
def test_price_goes_up_all_day(self):
actual = get_max_profit([1, 6, 7, 9])
expected = 8
self.assertEqual(actual, expected)
def test_price_goes_down_all_day(self):
actual = get_max_profit([9, 7, 4, 1])
expected = -2
self.assertEqual(actual, expected)
def test_price_stays_the_same_all_day(self):
actual = get_max_profit([1, 1, 1, 1])
expected = 0
self.assertEqual(actual, expected)
def test_error_with_empty_prices(self):
with self.assertRaises(Exception):
get_max_profit([])
def test_error_with_one_price(self):
with self.assertRaises(Exception):
get_max_profit([1])
unittest.main(verbosity=2)