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Add python code for queue

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pengchzn 2022-11-30 12:15:50 +08:00
parent b1b5094436
commit a2b7586c98
4 changed files with 248 additions and 12 deletions
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91
codes/python/chapter_stack_and_queue/array_queue.py
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'''
File: array_queue.py
Created Time: 2022-11-25
Author: Krahets (krahets@163.com)
Created Time: 2022-11-29
Author: Peng Chen (pengchzn@gmail.com)
'''
import sys, os.path as osp
import os.path as osp
import sys
sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
from include import *
""" 基于环形数组实现的队列 """
class ArrayQueue:
def __init__(self, size):
self.nums = [None] * size # 用于存储队列元素的数组
self.front = 0 # 头指针，指向队首
self.rear = 0 # 尾指针，指向队尾 + 1
""" 获取队列的容量 """
def capacity(self):
return len(self.nums)
""" 获取队列的长度 """
def size(self):
# 由于将数组看作为环形，可能 rear < front ，因此需要取余数
return (self.capacity() + self.rear - self.front) % self.capacity()
""" 判断队列是否为空 """
def is_empty(self):
return len(self.nums)==0
""" 入队 """
def put(self, val):
if self.size() == self.capacity():
print("队列已满")
return False
# 尾结点后添加 num
self.nums[self.rear] = val
# 尾指针向后移动一位，越过尾部后返回到数组头部
self.rear = (self.rear + 1) % self.capacity()
""" 出队 """
def get(self):
# 删除头结点
if self.is_empty():
print("队列为空")
return False
num = self.nums[self.front]
self.nums[self.front] = None
# 队头指针向后移动，越过尾部后返回到数组头部
self.front = (self.front + 1) % self.capacity()
return num
""" 访问队首元素 """
def peek(self):
# 删除头结点
if self.is_empty():
return 1
return self.nums[self.front]
""" 访问指定位置元素 """
def get_index(self, index):
if index >= self.size():
return -1
return self.nums[(self.front + index) % self.capacity()]
if __name__ == "__main__":
""" 初始化队列 """
queue = ArrayQueue(5)
""" 元素入队 """
queue.put(1)
queue.put(3)
queue.put(2)
queue.put(5)
queue.put(4)
print("队列 queue = ", queue.nums)
""" 访问队首元素 """
peek = queue.peek()
print("队首元素 peek = ", peek)
""" 元素出队 """
get = queue.get()
print("出队元素 get = ", get)
print("出队后 queue = ", queue.nums)
""" 获取队列的长度 """
size = queue.size()
print("队列长度 size = ", size)
""" 判断队列是否为空 """
is_empty = queue.is_empty()
print("队列是否为空 = ", is_empty)

43
codes/python/chapter_stack_and_queue/deque.py
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'''
File: deque.py
Created Time: 2022-11-25
Author: Krahets (krahets@163.com)
Created Time: 2022-11-29
Author: Peng Chen (pengchzn@gmail.com)
'''
import sys, os.path as osp
import os.path as osp
import sys
sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
from include import *
from collections import deque
if __name__ == "__main__":
""" 初始化双向队列 """
duque = deque()
""" 元素入队 """
duque.append(2) # 添加至队尾
duque.append(5)
duque.append(4)
duque.appendleft(3) # 添加至队首
duque.appendleft(1)
print("双向队列 duque = ", duque)
""" 访问队首元素 """
peekFirst = duque[0] # 队首元素
print("队首元素 peekFirst = ", peekFirst)
peekLast = duque[-1] # 队尾元素
print("队尾元素 peekLast = ", peekLast)
""" 元素出队 """
popFirst = duque.pop() # 队首元素出队
print("队首出队元素 popFirst= ", popFirst)
print("队首出队后 duque = ", duque)
popLast = duque.popleft() # 队尾元素出队
print("队尾出队元素 popLast= ", popLast)
print("队尾出队后 duque = ", duque)
""" 获取队列的长度 """
size = len(duque)
print("队列长度 size = ", size)
""" 判断队列是否为空 """
is_empty = len(duque) == 0
print("队列是否为空 = ", is_empty)

88
codes/python/chapter_stack_and_queue/linkedlist_queue.py
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'''
File: linkedlist_queue.py
Created Time: 2022-11-25
Author: Krahets (krahets@163.com)
Created Time: 2022-11-29
Author: Peng Chen (pengchzn@gmail.com)
'''
import sys, os.path as osp
import os.path as osp
import sys
sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
from include import *
""" 基于链表实现的队列 """
class LinkedListQueue:
def __init__(self):
self.__front = 0 # 头结点 front
self.__rear = 0 # 尾结点 rear
self.__size = 0
""" 获取队列的长度 """
def size(self):
return self.__size
""" 判断队列是否为空 """
def is_empty(self):
return not self.__front
""" 入队 """
def put(self, num):
# 尾结点后添加 num
node = ListNode(num)
# 如果队列为空，则令头、尾结点都指向该结点
if self.__front == 0:
self.__front = node
self.__rear = node
# 如果队列不为空，则将该结点添加到尾结点后
else:
self.__rear.next = node
self.__rear = node
self.__size += 1
""" 出队 """
def get(self):
num = self.peek()
# 删除头结点
self.__front = self.__front.next
self.__size -= 1
return num
""" 访问队首元素 """
def peek(self):
if self.size() == 0:
return -1
return self.__front.val
def to_array(self):
queue = []
temp = self.__front
while temp:
queue.append(temp.val)
temp = temp.next
return queue
if __name__ == "__main__":
""" 初始化队列 """
queue = LinkedListQueue()
""" 元素入队 """
queue.put(1)
queue.put(3)
queue.put(2)
queue.put(5)
queue.put(4)
print("队列 queue = ", queue.to_array())
""" 访问队首元素 """
peek = queue.peek()
print("队首元素 front = ", peek)
""" 元素出队 """
get = queue.get()
print("出队元素 get = ", get)
print("出队后 queue = ", queue.to_array())
""" 获取队列的长度 """
size = queue.size()
print("队列长度 size = ", size)
""" 判断队列是否为空 """
is_empty = queue.is_empty()
print("队列是否为空 = ", is_empty)

38
codes/python/chapter_stack_and_queue/queue.py
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'''
File: queue.py
Created Time: 2022-11-25
Author: Krahets (krahets@163.com)
Created Time: 2022-11-29
Author: Peng Chen (pengchzn@gmail.com)
'''
import sys, os.path as osp
import os.path as osp
import sys
sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
from include import *
import queue
if __name__ == "__main__":
""" 初始化队列 """
queue = queue.Queue()
""" 元素入队 """
queue.put(1)
queue.put(3)
queue.put(2)
queue.put(5)
queue.put(4)
print("队列 queue = ", queue.queue)
""" 访问队首元素 """
peek = queue.queue[0]
print("队首元素 peek = ", peek)
""" 元素出队 """
get = queue.get()
print("出队元素 get = ", get)
print("出队后 queue = ", queue.queue)
""" 获取队列的长度 """
size = queue.qsize()
print("队列长度 size = ", size)
""" 判断队列是否为空 """
is_empty = queue.empty()
print("队列是否为空 = ", is_empty)