Created
December 14, 2016 01:18
Star
You must be signed in to star a gist
Interview Cake Solutions
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
import typing | |
import unittest | |
class TreeNode: | |
def __init__(self, left=None, right=None): | |
self.left = left | |
self.right = right | |
def is_superbalanced(self): | |
path = [(0, self)] | |
max_depth = None | |
while path: | |
depth, node = path.pop() | |
if node.right: | |
path.append((depth + 1, node.right)) | |
if node.left: | |
path.append((depth + 1, node.left)) | |
if node.left is None and node.right is None: | |
if not max_depth: | |
max_depth = depth | |
# Incorrect test. | |
if abs(max_depth - depth) > 1: | |
return False | |
return True | |
class TestIsSuperbalanced(unittest.TestCase): | |
def test_simple_ok(self): | |
root = TreeNode( | |
TreeNode(), | |
TreeNode()) | |
self.assertTrue(root.is_superbalanced()) | |
def test_simple_fail(self): | |
root = TreeNode( | |
TreeNode(TreeNode(TreeNode())), | |
TreeNode()) | |
self.assertFalse(root.is_superbalanced()) | |
def test_staggered_fail(self): | |
# TODO | |
class TempTracker: | |
def __init__(self): | |
self._count = 0 | |
self._seen = [0] * (110 + 1) | |
self._sum = 0 | |
self.max = None | |
self.min = None | |
self.mean = None | |
self.mode = 0 | |
def insert(self, temperature): | |
self._count += 1 | |
self._seen[temperature] += 1 | |
self._sum += temperature | |
if self.max is None or temperature > self.max: | |
self.max = temperature | |
if self.min is None or temperature < self.min: | |
self.min = temperature | |
self.mean = self._sum / self._count | |
if self._seen[temperature] > self._seen[self.mode]: | |
self.mode = temperature | |
class TestTempTracker(unittest.TestCase): | |
def test_basic(self): | |
unit = TempTracker() | |
for t in [0, 1, 1, 2]: | |
unit.insert(t) | |
self.assertEqual(unit.max, 2) | |
self.assertEqual(unit.min, 0) | |
self.assertEqual(unit.mean, 1.0) | |
self.assertEqual(unit.mode, 1) | |
def test_multi_mode(self): | |
unit = TempTracker() | |
for t in [1, 3, 6, 3, 1, 3]: | |
unit.insert(t) | |
self.assertEqual(unit.min, 1) | |
self.assertEqual(unit.max, 6) | |
self.assertEqual(unit.mode, 3) | |
Rectangle = typing.NamedTuple('Rectangle', [ | |
('left_x', int), | |
('bottom_y', int), | |
('width', int), | |
('height', int)]) | |
def rectangle_collides(a, b): | |
def _overlap(a_origin, a_mag, b_origin, b_mag): | |
if a_origin <= b_origin <= a_origin + a_mag: | |
return b_origin, min(a_mag - (b_origin - a_origin), b_mag) | |
elif b_origin <= a_origin <= b_origin + b_mag: | |
return a_origin, min(b_mag - (a_origin - b_origin), a_mag) | |
return None, None | |
# Check overlap on the X dimension | |
left_x, width = _overlap(a.left_x, a.width, b.left_x, b.width) | |
bottom_y, height = _overlap(a.bottom_y, a.height, b.bottom_y, b.height) | |
if left_x is None or width == 0 \ | |
or bottom_y is None or height == 0: | |
return None | |
return Rectangle(left_x, bottom_y, width, height) | |
class TestRectangleCollides(unittest.TestCase): | |
cases = [ | |
((Rectangle(0, 0, 1, 1), Rectangle(5, 5, 1, 1)), None), | |
((Rectangle(0, 0, 1, 1), Rectangle(0, 0, 1, 1)), Rectangle(0, 0, 1, 1)), | |
((Rectangle(0, 0, 3, 3), Rectangle(1, 0, 2, 2)), Rectangle(1, 0, 2, 2)), | |
((Rectangle(0, 0, 1, 1), Rectangle(1, 1, 1, 1)), None), | |
] | |
def test_case(self): | |
for args, expected in self.cases: | |
self.assertEqual(rectangle_collides(*args), expected) | |
def make_change(amount, denominations): | |
coins_per_amount = [0] * (amount + 1) | |
coins_per_amount[0] = 1 | |
for coin in denominations: | |
for amount in range(coin, len(coins_per_amount)): | |
coins_per_amount[amount] += coins_per_amount[amount - coin] | |
return coins_per_amount[amount] | |
class TestMakeChange(unittest.TestCase): | |
cases = [ | |
((4, [1, 2, 3]), 4), | |
((7, [2, 4]), 0), | |
] | |
def test_cases(self): | |
for args, expected in self.cases: | |
self.assertEqual(make_change(*args), expected) | |
def merge_ranges(meetings): | |
rv = [] | |
current_start, current_end = meetings[0] | |
for start, end in sorted(meetings): | |
if start > current_end: | |
rv.append((current_start, current_end)) | |
current_start, current_end = start, end | |
elif end > current_end: | |
current_end = end | |
rv.append((current_start, current_end)) | |
return rv | |
class TestMergeRanges(unittest.TestCase): | |
def test_example(self): | |
v = [(0, 1), (3, 5), (4, 8), (10, 12), (9, 10)] | |
self.assertEqual( | |
merge_ranges(v), | |
[(0, 1), (3, 8), (9, 12)]) | |
def test_touching(self): | |
self.assertEqual( | |
merge_ranges([(1, 2), (2, 3)]), | |
[(1, 3)]) | |
def test_subsume(self): | |
self.assertEqual( | |
merge_ranges([(1, 5), (2, 3)]), | |
[(1, 5)]) | |
def test_merged_merge(self): | |
v = [(1, 10), (2, 6), (3, 5), (7, 9)] | |
self.assertEqual( | |
merge_ranges(v), | |
[(1, 10)]) | |
def highest_product(list_of_ints): | |
pproducts = [1, 1, 1] | |
nproducts = [-1, -1] | |
for x in list_of_ints: | |
if x >= pproducts[0]: | |
pproducts = [x, pproducts[0], pproducts[1]] | |
elif x <= nproducts[0]: | |
nproducts = [x, nproducts[0]] | |
high_pproduct = pproducts[0] * pproducts[1] * pproducts[2] | |
high_nproduct = nproducts[0] * nproducts[1] * pproducts[0] | |
return max(high_pproduct, high_nproduct) | |
class TestHighestProduct(unittest.TestCase): | |
def test_up(self): | |
v = [1, 2, 3, 4] | |
self.assertEqual(highest_product(v), 24) | |
def test_gotcha_a(self): | |
v = [-10, -10, 1, 3, 2] | |
self.assertEqual(highest_product(v), 300) | |
def get_products_of_all_ints_except_at_index(ints): | |
def _(rv, a): | |
acc = 1 | |
for idx, v in enumerate(a): | |
rv[idx] = rv[idx] * acc | |
acc = acc * v | |
return rv | |
a = [1] * len(ints) | |
right = _(a[::-1], ints[::-1])[::-1] | |
left = _(right, ints) | |
return left | |
class TestGetProductsOfAllIntsExceptAtIndex(unittest.TestCase): | |
def test_example(self): | |
v = [1, 7, 3, 4] | |
self.assertEqual( | |
get_products_of_all_ints_except_at_index(v), | |
[84, 12, 28, 21]) | |
def test_with_zero(self): | |
v = [1, 7, 3, 4, 0] | |
self.assertEqual( | |
get_products_of_all_ints_except_at_index(v), | |
[0, 0, 0, 0, 84]) | |
def get_max_profit(prices): | |
min_price = prices[0] | |
best_price = prices[1] - prices[0] | |
for price in prices[1:]: | |
best_price = max(best_price, price - min_price) | |
min_price = min(min_price, price) | |
return best_price | |
class TestGetMaxProfit(unittest.TestCase): | |
def test_example(self): | |
stock_prices_yesterday = [10, 7, 5, 8, 11, 9] | |
self.assertEqual(get_max_profit(stock_prices_yesterday), 6) | |
def test_out_of_order(self): | |
stock_prices_yesterday = [100, 1, 5] | |
self.assertEqual(get_max_profit(stock_prices_yesterday), 4) | |
def test_down(self): | |
stock_prices_yesterday = [1, 2, 3] | |
self.assertEqual(get_max_profit(stock_prices_yesterday), 2) | |
def test_up(self): | |
stock_prices_yesterday = [3, 2, 1] | |
self.assertEqual(get_max_profit(stock_prices_yesterday), -1) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment