82. 删除排序链表中的重复元素 II @Python @Go

原题

https://leetcode.cn/problems/remove-duplicates-from-sorted-list-ii/description/

思路

虚拟节点 + 遍历

复杂度

时间：O(n)
空间：O(n)

Python代码

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def deleteDuplicates(self, head: Optional[ListNode]) -> Optional[ListNode]:
        dummy = cur = ListNode(0, head)
        while head:
            # 存在重复数字, 移动指针
            if head.next and head.val == head.next.val:
                while head.next and head.val == head.next.val:
                    head = head.next
                cur.next = head.next
            else:
                cur.next = head
                cur = cur.next
            head = head.next
        return dummy.next

Go代码

/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */
func deleteDuplicates(head *ListNode) *ListNode {
	dummy := &ListNode{0, head}
	cur := dummy
	for head != nil {
		// 存在重复数字, 移动指针
		if head.Next != nil && head.Val == head.Next.Val {
			for head.Next != nil && head.Val == head.Next.Val {
				head = head.Next
			}
			cur.Next = head.Next
		} else {
			cur.Next = head
			cur = cur.Next
		}
		head = head.Next
	}
	return dummy.Next
}