82.remove-duplicates-from-sorted-list-ii.go

/*
 * @lc app=leetcode id=82 lang=golang
 *
 * [82] Remove Duplicates from Sorted List II
 */

// @lc code=start
/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */
func deleteDuplicates(head *ListNode) *ListNode {
	if head == nil || head.Next == nil {
		return head
	}
	dummy := &ListNode{}
	dummy.Next = head
	cur := dummy.Next
	pre := dummy
	for cur.Next != nil {
		for cur.Next != nil && cur.Val == cur.Next.Val {
			cur = cur.Next
		}
		if pre.Next == cur {
			pre = pre.Next
		} else {
			pre.Next = cur.Next
		}
		if cur.Next != nil {
			cur = cur.Next
		}
	}
	return dummy.Next
}

// @lc code=end