补充第 300 ~ 399 题的题目解析（增加 13 道题）

Author: itcharge

codes/python/03_stack_queue_hash_table/queue_deque.py

@@ -0,0 +1,217 @@
+class Node:
+    """双向链表节点"""
+    def __init__(self, value):
+        self.value = value     # 节点值
+        self.prev = None       # 指向前一个节点的指针
+        self.next = None       # 指向后一个节点的指针
+
+class Deque:
+    """双向队列实现 - 链式存储"""
+    def __init__(self):
+        """初始化空双向队列"""
+        # 创建哨兵节点
+        self.head = Node(0)    # 头哨兵节点
+        self.tail = Node(0)    # 尾哨兵节点
+        self.head.next = self.tail
+        self.tail.prev = self.head
+        self.size = 0          # 队列大小
+    
+    def is_empty(self):
+        """判断队列是否为空"""
+        return self.size == 0
+    
+    def get_size(self):
+        """获取队列大小"""
+        return self.size
+    
+    def push_front(self, value):
+        """队头入队"""
+        new_node = Node(value)
+        # 在头哨兵节点后插入新节点
+        new_node.next = self.head.next
+        new_node.prev = self.head
+        self.head.next.prev = new_node
+        self.head.next = new_node
+        self.size += 1
+    
+    def push_back(self, value):
+        """队尾入队"""
+        new_node = Node(value)
+        # 在尾哨兵节点前插入新节点
+        new_node.prev = self.tail.prev
+        new_node.next = self.tail
+        self.tail.prev.next = new_node
+        self.tail.prev = new_node
+        self.size += 1
+    
+    def pop_front(self):
+        """队头出队"""
+        if self.is_empty():
+            raise Exception('Deque is empty')
+        
+        # 删除头哨兵节点后的第一个节点
+        node = self.head.next
+        self.head.next = node.next
+        node.next.prev = self.head
+        self.size -= 1
+        return node.value
+    
+    def pop_back(self):
+        """队尾出队"""
+        if self.is_empty():
+            raise Exception('Deque is empty')
+        
+        # 删除尾哨兵节点前的第一个节点
+        node = self.tail.prev
+        self.tail.prev = node.prev
+        node.prev.next = self.tail
+        self.size -= 1
+        return node.value
+    
+    def peek_front(self):
+        """查看队头元素"""
+        if self.is_empty():
+            raise Exception('Deque is empty')
+        return self.head.next.value
+    
+    def peek_back(self):
+        """查看队尾元素"""
+        if self.is_empty():
+            raise Exception('Deque is empty')
+        return self.tail.prev.value
+
+class ArrayDeque:
+    """双向队列实现 - 顺序存储"""
+    def __init__(self, capacity=100):
+        """初始化双向队列"""
+        self.capacity = capacity
+        self.queue = [None] * capacity
+        self.front = 0        # 队头指针
+        self.rear = 0         # 队尾指针
+        self.size = 0         # 队列大小
+    
+    def is_empty(self):
+        """判断队列是否为空"""
+        return self.size == 0
+    
+    def is_full(self):
+        """判断队列是否已满"""
+        return self.size == self.capacity
+    
+    def get_size(self):
+        """获取队列大小"""
+        return self.size
+    
+    def push_front(self, value):
+        """队头入队"""
+        if self.is_full():
+            raise Exception('Deque is full')
+        
+        # 队头指针向前移动
+        self.front = (self.front - 1) % self.capacity
+        self.queue[self.front] = value
+        self.size += 1
+    
+    def push_back(self, value):
+        """队尾入队"""
+        if self.is_full():
+            raise Exception('Deque is full')
+        
+        self.queue[self.rear] = value
+        # 队尾指针向后移动
+        self.rear = (self.rear + 1) % self.capacity
+        self.size += 1
+    
+    def pop_front(self):
+        """队头出队"""
+        if self.is_empty():
+            raise Exception('Deque is empty')
+        
+        value = self.queue[self.front]
+        # 队头指针向后移动
+        self.front = (self.front + 1) % self.capacity
+        self.size -= 1
+        return value
+    
+    def pop_back(self):
+        """队尾出队"""
+        if self.is_empty():
+            raise Exception('Deque is empty')
+        
+        # 队尾指针向前移动
+        self.rear = (self.rear - 1) % self.capacity
+        value = self.queue[self.rear]
+        self.size -= 1
+        return value
+    
+    def peek_front(self):
+        """查看队头元素"""
+        if self.is_empty():
+            raise Exception('Deque is empty')
+        return self.queue[self.front]
+    
+    def peek_back(self):
+        """查看队尾元素"""
+        if self.is_empty():
+            raise Exception('Deque is empty')
+        return self.queue[(self.rear - 1) % self.capacity]
+
+# 测试代码
+if __name__ == "__main__":
+    print("=== 链式存储双向队列测试 ===")
+    deque = Deque()
+    
+    # 测试队尾入队
+    deque.push_back(1)
+    deque.push_back(2)
+    deque.push_back(3)
+    print(f"队尾入队后，队列大小: {deque.get_size()}")
+    print(f"队头元素: {deque.peek_front()}")
+    print(f"队尾元素: {deque.peek_back()}")
+    
+    # 测试队头入队
+    deque.push_front(0)
+    print(f"队头入队后，队列大小: {deque.get_size()}")
+    print(f"队头元素: {deque.peek_front()}")
+    print(f"队尾元素: {deque.peek_back()}")
+    
+    # 测试出队操作
+    print(f"队头出队: {deque.pop_front()}")
+    print(f"队尾出队: {deque.pop_back()}")
+    print(f"出队后，队列大小: {deque.get_size()}")
+    
+    print("\n=== 顺序存储双向队列测试 ===")
+    array_deque = ArrayDeque(capacity=5)
+    
+    # 测试队尾入队
+    array_deque.push_back(1)
+    array_deque.push_back(2)
+    array_deque.push_back(3)
+    print(f"队尾入队后，队列大小: {array_deque.get_size()}")
+    print(f"队头元素: {array_deque.peek_front()}")
+    print(f"队尾元素: {array_deque.peek_back()}")
+    
+    # 测试队头入队
+    array_deque.push_front(0)
+    print(f"队头入队后，队列大小: {array_deque.get_size()}")
+    print(f"队头元素: {array_deque.peek_front()}")
+    print(f"队尾元素: {array_deque.peek_back()}")
+    
+    # 测试出队操作
+    print(f"队头出队: {array_deque.pop_front()}")
+    print(f"队尾出队: {array_deque.pop_back()}")
+    print(f"出队后，队列大小: {array_deque.get_size()}")
+    
+    # 测试循环队列特性
+    print("\n=== 循环队列特性测试 ===")
+    array_deque.push_back(4)
+    array_deque.push_back(5)
+    array_deque.push_front(6)
+    print(f"队列大小: {array_deque.get_size()}")
+    print(f"是否已满: {array_deque.is_full()}")
+    
+    # 清空队列
+    while not array_deque.is_empty():
+        print(f"出队: {array_deque.pop_front()}")
+    
+    print(f"队列是否为空: {array_deque.is_empty()}")