def test_dequeue(self):
dequeue = Dequeue()
dequeue.push(1)
dequeue.push(2)
dequeue.push(3)
dequeue.push(4)
self.assertEqual(1, dequeue.pop())
self.assertEqual(4, dequeue.leftpop())
self.assertEqual(2, dequeue.pop())
self.assertEqual(3, dequeue.leftpop())
class MinQueue():
def __init__(self):
self.capacity = 2
self.__size = 0
self.queue = [0] * self.capacity
self.front = 0
self.rear = 0
## a monotonic dequeue to maintain the min value , the val in decreasing order in the dequeue
self.__min_dequeue = Dequeue()
def append(self, e):
if self.full():
self.__adjust_capacity()
idx = self.rear
self.queue[self.rear] = e
self.rear = (self.rear + 1) % self.capacity
self.__size += 1
self.__add_to_min_queue(idx)
def pop(self):
if self.empty():
return None
e = self.queue[self.front]
self.front = (self.front + 1) % self.capacity
self.__size -= 1
while not self.__min_dequeue.empty() and self.__isvalid_index(
self.__min_dequeue.peak()) == False:
self.__min_dequeue.pop()
return e
def __isvalid_index(self, idx):
if self.empty():
return False
if self.full():
return True
if self.rear > self.front:
return True if self.front <= idx < self.rear else False
if self.rear < self.front:
return True if (idx >= self.front or idx < self.rear) else False
return False
def __add_to_min_queue(self, idx):
while not self.__min_dequeue.empty() and self.queue[idx] <= self.queue[
self.__min_dequeue.peakRight()]:
self.__min_dequeue.popRight()
self.__min_dequeue.append(idx)
def min(self):
if self.empty():
return None
return self.queue[self.__min_dequeue.peak()]
def peek(self):
return None if self.empty() else self.queue[self.rear]
def empty(self):
return self.__size == 0
def full(self):
return self.__size == self.capacity
def size(self):
return self.__size
def __adjust_capacity(self):
if not self.full():
return
new_capacity = self.capacity * 2
new_queue = [0] * new_capacity
idx_in_queue = self.front
idx_in_new_queue = 0
e = self.queue[idx_in_queue]
new_queue[idx_in_new_queue] = e
idx_in_queue = (idx_in_queue + 1) % self.capacity
idx_in_new_queue += 1
while idx_in_queue != self.front:
e = self.queue[idx_in_queue]
new_queue[idx_in_new_queue] = e
idx_in_queue = (idx_in_queue + 1) % self.capacity
idx_in_new_queue += 1
self.queue = new_queue
self.front = 0
self.rear = self.capacity
self.capacity = new_capacity
