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ArrayQueue.py
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54 lines (54 loc) · 1.56 KB
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class Array:
def __init__(self, size=32):
self._size = size
self._items = [None]*32
def __getitem__(self, index):
return self._items[index]
def __setitem__(self, index, value):
self._items[index] = value
def __len__(self):
return self._size
def clear(self, value=None):
for i in range(len(self._items)):
self._items[i] = value
def __iter__(self):
for i in self._items:
yield i
class FullError(Exception):
pass
class ArrayQueue:
'''定长的队列，当队列满了之后再添加元素，会覆盖掉第一个添加的一个元素,从头开始添加。'''
def __init__(self, maxsize):
self.maxsize = maxsize
self.array = Array(maxsize)
self.head = 0
self.tail = 0
def push(self, value):
if len(self.array) > self.maxsize:
raise FullError('The queue is full')
self.array[self.head%self.maxsize] = value
self.head += 1
def pop(self):
value = self.array[self.tail%self.maxsize]
self.tail += 1
return value
def __len__(self):
return self.head - self.tail
def test_array_queue():
size = 5
q = ArrayQueue(size)
for i in range(size):
q.push(i)
assert len(q) == size
assert q.pop() == 0
assert q.pop() == 1
q.push(5)
assert len(q) == 4
assert q.pop() == 2
assert q.pop() == 3
assert q.pop() == 4
assert q.pop() == 5
assert len(q) == 0
print('Test Successful')
if __name__ == "__main__":
test_array_queue()