class QueueUsingStacks():
def __init__(self):
from calvin.data_structure.stack import Stack
self.stack1=Stack()
self.stack2=Stack()
def isEmpty(self):
return self.stack1.isEmpty() and self.stack2.isEmpty()
def enqueue(self, item):
self.stack1.push(item)
def dequeue(self):
self.__rotateStack()
return self.stack2.pop()
def peek(self):
self.__rotateStack()
return self.stack2.peek()
def __rotateStack(self):
if (self.isEmpty()):
raise Exception("queue is empty!")
if self.stack2.isEmpty():
while not self.stack1.isEmpty():
self.stack2.push(self.stack1.pop())
def size(self):
return self.stack1.size() + self.stack2.size()
def dfs_iterative(self, root):
s = Stack()
s.push(root)
while s.size() > 0:
vertex = s.pop()
self.vertices.append(vertex.get_vertex())
for neighbor in vertex.get_child():
if neighbor and neighbor.state == State.UNVISITED:
s.push(neighbor)
vertex.state = State.VISITED
def simplifyPath(self, path):
s = Stack()
skip = {"..", ".", ""}
for dir in path.split("/"):
if (dir == ".." and not s.isEmpty()):
s.pop()
elif dir not in skip:
s.push(dir)
res = ""
siter = iter(s)
for elem in siter:
res = "/" + elem + res
return "/" if not res else res
def __string_bs_caps(self, s):
BACKSLASH = False
CAPSLOCK = False
st = Stack()
for char in s:
if char == '\\':
BACKSLASH = not BACKSLASH
else:
if BACKSLASH and char == 'b':
st.pop()
BACKSLASH = not BACKSLASH
elif BACKSLASH and char == 'c':
CAPSLOCK = not CAPSLOCK
BACKSLASH = not BACKSLASH
else:
st.push(char.upper() if CAPSLOCK else char)
if CAPSLOCK:
CAPSLOCK = not CAPSLOCK
result = ''
for i in range(st.size()):
result = st.pop() + result
return result
def baseball_game(self, arr):
if arr is None:
return None
sum = 0
stack = Stack()
for x in arr:
if x.isdigit() or (x[0] == '-' and x[1:].isdigit()):
sum += int(x)
stack.push(x)
elif x == 'C':
sum -= int(stack.pop())
elif x == 'D':
sum += 2 * int(stack.peek())
stack.push(2 * int(stack.peek()))
elif x == '+':
curr = stack.pop()
prev = 0
if not stack.isEmpty():
prev = stack.pop()
sum += (int(curr) + int(prev))
stack.push(int(curr) + int(prev))
stack.push(curr)
return sum
def test_sort(self):
s1 = Stack()
s1.push(1)
s1.push(2)
s1.push(4)
s1.push(9)
s1.push(12)
s1.push(11)
s1.push(3)
expected = [1, 2, 3, 4, 9, 11, 12]
for i in enumerate(iter(self.fixture.sort(s1))):
self.assertEqual(expected[i[0]], i[1])
s1.push(1)
s1.push(2)
s1.push(4)
s1.push(9)
s1.push(12)
s1.push(11)
s1.push(3)
self.fixture.sortStack(s1)
for i in range(s1.size()):
self.assertEqual(expected[i], s1.pop())
class TestStack(unittest.TestCase):
def setUp(self):
self.fixture = Stack()
self.assertTrue(self.fixture.isEmpty())
def test_iter(self):
self.fixture.push(1)
self.fixture.push(2)
self.fixture.push(3)
stackiter = iter(self.fixture)
expected = [1, 2, 3]
for i in stackiter:
self.assertEqual(expected.pop(), i)
def test_push_various_types(self):
self.fixture.push(6)
self.fixture.push(True)
self.fixture.push('cat')
self.assertEqual('cat', self.fixture.peek())
self.assertFalse(self.fixture.isEmpty())
self.assertEqual(3, self.fixture.size())
def test_pop_items_out(self):
self.fixture.push(6)
self.fixture.push(True)
self.fixture.push('cat')
self.assertEqual('cat', self.fixture.peek())
self.fixture.pop()
self.assertEqual(True, self.fixture.peek())
self.fixture.pop()
self.assertEqual(6, self.fixture.peek())
self.fixture.pop()
self.assertTrue((self.fixture.isEmpty()))
self.assertRaises(IndexError, self.fixture.pop)
self.assertRaises(Exception, self.fixture.peek)
def test_sort(self):
s1 = Stack()
s1.push(1)
s1.push(2)
s1.push(4)
s1.push(9)
s1.push(12)
s1.push(11)
s1.push(3)
expected = [1, 2, 3, 4, 9, 11, 12]
for i in enumerate(iter(self.fixture.sort(s1))):
self.assertEqual(expected[i[0]], i[1])
s1.push(1)
s1.push(2)
s1.push(4)
s1.push(9)
s1.push(12)
s1.push(11)
s1.push(3)
self.fixture.sortStack(s1)
for i in range(s1.size()):
self.assertEqual(expected[i], s1.pop())