feat: queue

Author: juwenzhang

Python_queue_by_link.py

@@ -0,0 +1,63 @@
+# 使用我们的链表作为底层的数据结构实现队列
+# from multiprocessing import Queue
+
+class Queue_Node(object):
+    def __init__(self, val, back = None):
+        self.val = val
+        self.back = back  # 记录的是入队的节点指针
+
+class Queue(object):
+    # 构造函数
+    def __init__(self):
+        self.__head = self.__end = Queue_Node(None)
+
+    # 开始我们的入队操作
+    def push(self, data):
+        self.__head.back = Queue_Node(data)
+        # 然后将我们的头节点执行现在新加的节点,实现节点的后移
+        self.__head = self.__head.back
+
+    # 出队的操作实现
+    def pop(self):
+        # 实现的是先进先出
+        # 我们这里的 end 节点是一直不用更新的，一直指向的是最初的头节点
+        if self.__head == self.__end:
+            raise Exception("queue is empty")
+        self.__end = self.__end.back
+        return self.__end.val
+
+    def show_front_val(self):
+        if self.__head.back is None:
+            raise Exception("queue is empty")
+        return self.__head.back.val
+
+    def show_end_val(self):
+        if self.__end:
+            return self.__end.val
+        raise Exception("queue is empty")
+
+
+if __name__ == "__main__":
+    queue = Queue()
+
+    print(queue.show_end_val())
+    queue.push(1)
+    # print(queue.show_end_val())
+    queue.push(2)
+    print(queue.show_end_val())
+    queue.push(3)
+    print(queue.show_end_val())
+    queue.push(4)
+    print(queue.show_end_val())
+
+    # 开始出栈
+    print(queue.show_end_val())
+    print(queue.pop())
+    print(queue.show_end_val())
+    print(queue.pop())
+    print(queue.show_end_val())
+    print(queue.pop())
+    print(queue.pop())
+
+
+    # https://developer.aliyun.com/article/953777  队列的实现场景，消息队列的实现