双向链表中的重复项

class Node:
    def __init__(self, value):
        self.value = value
        self.prev = None
        self.next = None

def remove_duplicates(head):
    current = head
    while current:
        runner = current.next
        while runner:
            if runner.value == current.value:
                runner.prev.next = runner.next
                if runner.next:
                    runner.next.prev = runner.prev
            runner = runner.next
        current = current.next

# 示例用法
# 创建链表
node1 = Node(1)
node2 = Node(2)
node3 = Node(2)
node4 = Node(3)
node1.next = node2
node2.prev = node1
node2.next = node3
node3.prev = node2
node3.next = node4
node4.prev = node3

# 处理重复项
remove_duplicates(node1)

# 输出链表
current = node1
while current:
    print(current.value)
    current = current.next