Merge pull request #53 from pengchzn/master

Add python code for queue

codes/python/chapter_stack_and_queue/array_queue.py

@@ -1,10 +1,110 @@
 '''
 File: array_queue.py
-Created Time: 2022-11-25
-Author: Krahets (krahets@163.com)
+Created Time: 2022-12-01
+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 (self.__rear - self.__front) == 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]
+        # 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():
+            print("队列为空")
+            return False
+        return self.__nums[self.__front]
+
+    """ 访问指定位置元素 """
+    def get_index(self, index):
+        if index >= self.size():
+            print("索引越界")
+            return False
+        return self.__nums[(self.__front + index) % self.capacity()]
+
+    """ 返回列表用于打印 """
+    def to_list(self):
+        res = [None] * self.size()
+        j = self.__front
+        for i in range(self.size()):
+            res[i] = self.__nums[(j % self.capacity())]
+            j += 1
+        return res
+
+
+if __name__ == "__main__":
+    """ 初始化队列 """
+    queue = ArrayQueue(10)
+
+    """ 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_list())
+
+    """ 访问队首元素 """
+    peek = queue.peek()
+    print("队首元素 peek = ", peek)
+
+    """ 访问索引 index 处元素 """
+    num = queue.get_index(3)
+    print("队列索引 3 处的元素为 num =", num)
+
+    """ 元素出队 """
+    get = queue.get()
+    print("出队元素 get = ", get)
+    print("出队后 queue = ", queue.to_list())
+
+    """ 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)

codes/python/chapter_stack_and_queue/deque.py

@@ -1,10 +1,47 @@
 '''
 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)
+
+    """ 获取双向队列的长度 """
+    size = len(duque)
+    print("双向队列长度 size = ", size)
+
+    """ 判断双向队列是否为空 """
+    is_empty = len(duque) == 0
+    print("双向队列是否为空 = ", is_empty)

codes/python/chapter_stack_and_queue/linkedlist_queue.py

@@ -1,10 +1,94 @@
 '''
 File: linkedlist_queue.py
-Created Time: 2022-11-25
-Author: Krahets (krahets@163.com)
+Created Time: 2022-12-01
+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:
+            print("队列为空")
+            return False
+        return self.__front.val
+
+    """ 转化为列表用于打印 """
+    def to_list(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_list())
+
+    """ 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_list())
+
+    """ 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)

codes/python/chapter_stack_and_queue/queue.py

@@ -1,10 +1,42 @@
 '''
 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)