题目
解题
class ListNode:
def __init__(self, val=0, next=None):
self.val = val
self.next = next
class Solution:
def deleteDuplicates(self, head: ListNode) -> ListNode:
# 创建一个虚拟头结点
dummy = ListNode(0)
dummy.next = head
prev = dummy
while head:
# 检查当前节点是否是重复节点
if head.next and head.val == head.next.val:
# 找到所有重复的节点
while head.next and head.val == head.next.val:
head = head.next
# 跳过所有重复的节点
prev.next = head.next
else:
# 如果没有重复，更新 prev
prev = prev.next
# 移动到下一个节点
head = head.next
return dummy.next
# 工具函数
def print_linked_list(head: ListNode):
"""打印链表中的所有节点值"""
current = head
while current:
print(current.val, end=" -> " if current.next else "\n")
current = current.next
def list_to_linked_list(values):
"""将列表转换为链表"""
if not values:
return None
dummy = ListNode(0)
current = dummy
for value in values:
current.next = ListNode(value)
current = current.next
return dummy.next
def linked_list_to_list(head: ListNode):
"""将链表转换为列表"""
result = []
current = head
while current:
result.append(current.val)
current = current.next
return result
# 测试代码
if __name__ == "__main__":
# 测试案例
test_cases = [
([1, 1, 1, 2, 3], [2, 3]), # 删除重复元素后的链表
([1, 1, 2, 3, 3], [2]), # 删除重复元素后的链表
([1, 2, 3, 4, 5], [1, 2, 3, 4, 5]), # 无重复元素
([1, 1, 2, 2, 3, 3], []), # 所有元素都重复
([1, 2, 3, 4, 4, 5, 5], [1, 2, 3]) # 删除重复元素后的链表
]
for i, (values, expected) in enumerate(test_cases):
head = list_to_linked_list(values)
solution = Solution()
print(f"测试用例 {i + 1}: 原链表：", end="")
print_linked_list(head)
new_head = solution.deleteDuplicates(head)
result = linked_list_to_list(new_head)
print(f"删除重复元素后的链表：", end="")
print_linked_list(new_head)
assert result == expected, f"测试失败：期望 {expected}, 但得到 {result}"
print("测试通过\n")